Any future war against a peer or near-peer enemy will contain some measure of urban combat. A broad base of historical, demographic, sociopolitical, and military analysis makes that fact abundantly clear. As a result, militaries must be required to conduct both urban offense and defense operations. Military theorists have long described the defense as the strongest form of war, and current doctrine agrees. There are many reasons why a military would need to go into the defense in a campaign—to create conditions for the offense and regain the initiative, to destroy the enemy outright, to retain decisive terrain, or simply to slow the advance of a numerically or technologically superior force. A well-planned and -constructed urban defense could determine the success or failure of achieving a strategic objective, and could influence the outcome of a war.
Unlike other environments, such as wooded or mountainous areas, urban terrain contains unique characteristics that allow for a very strong and lethal defense to be conducted. The density, construction, and complexity of man-made physical terrain in urban areas allows soldiers to rapidly use or shape the environment to further strengthen a defense plan. These plans should seek to break apart an attacking formation, separate mounted from dismounted forces, limit the attacker’s ability to maneuver, degrade military technologies like intelligence, surveillance, and reconnaissance and aerial strike capabilities, maximize surprise, and either defeat the attackers in detail or buy time for other tactical, operational, and strategic actions.
Any military defending force must prepare to maximize its positions and plans. Doctrine is always a good place to start. We recommended any urban defender review the following doctrine before planning commences: Army Doctrinal Publication (ADP) 3-90, Offense and Defense, chapter 4, pages 4-1 to 4-18; Army Techniques Publication (ATP) 3-06, Urban Operations, chapter 5, pages 5-1 to 5-6; and Army Tactics, Techniques, and Procedures (ATTP) 3-06.11, Combined Arms Operations in Urban Terrain, chapter 3, pages 3-1 to 3-14, and Chapter 6, pages 6-1 to 6-12. Thirty-eight pages in total, these selections offer the foundation planners need before executing an urban defense. Of course, the operational and mission variables for each urban defense—the type of urban terrain, resources available, time, and enemy—could differ greatly from one another. However, there are important general characteristics of successful defenses: preparation, security, disruption, massing effects, and flexibility; primary types of defenses such as area, mobile, and retrograde; sequencing; different schemes of maneuver such as an area defense of a block or group of buildings, defense of key terrain, and defense of an urban strongpoint; seven steps to engagement area development; and other critical information that should be reviewed before starting a defense operation to significantly increase a unit’s effectiveness.
In addition to reviewing doctrine, history provides some innovative ideas that will allow a force to improve the quality of its urban defense. The following tactics were used during real-world urban battles and proved to be effective in support of an overall urban area defense plan. They include both conventional and unconventional measures that will assist in improving both hasty and deliberate urban defenses.
If choosing an area defense, which focuses on terrain, or assigning subordinate units to use perimeter defense of key terrain in the urban area, a strong tactic is to create strongpoints by reinforcing buildings or using preexisting structures that are already hard to destroy—for example, heavy-clad concrete structures like government buildings, apartments, and office complexes or banks. These strongpoint buildings become mini-fortresses within the city. If the defending force has the time and the engineer support it can bring in sandbags, lumber, steel girders, and other strengthening materials to harden the structure and create numerous bunkers within the fortress. Mines, wire, and other materials should be used to create obstacles around the building and seal any possible entryways, all to make it difficult for the enemy, who will require an abundance of time, fires, and resources to approach and clear the position. The critical analysis is choosing the right buildings to strongpoint, establishing multiple angles of attack by fire from the building, and constructing an obstacle network that prevents the attacker from simply bypassing or isolating the building to clear later.
In September 1942, during the Battle of Stalingrad, Russian Sergeant Yakov Pavlov and his platoon seized a four-story apartment building—later dubbed “Pavlov’s House”—overlooking a large square. The building had long lines of sight from three sides. Pavlov’s men place barbed wire and antipersonnel and antitank mines around the building, smashed and cut holes in walls to create interior walkways, and placed machine-gun firing points in the building’s corners. They would move to the cellar as indirect fire struck the top of the building or to higher floors when German Panzers approached so they could fire antitank rifles down onto the tanks’ vulnerable, thin roofs. Pavlov and his men held the building for fifty-eight days against numerous mechanized and combined arms attacks, causing an unknown number of German vehicle and soldier kills in the process.
Urban defenders must shape the terrain to facilitate their obstacles, engagement areas, ambushes, and battle positions. The sheer amount of military grade fortification material (e.g., concrete) gives an urban defender a great advantage. Some of the main goals of an urban defense are to funnel attacking forces into engagement areas, canalize them down a small number of avenues of approach, and constrain their ability to maneuver and mass forces. A method to accomplish this—and it is understood to be controversial, given the amount of destruction it generates—is to create rubble by destroying structures to produce broken concrete, rebar, stones, bricks, or solid material to include debris. Rubbled buildings can occur in urban warfare from an attacker’s preparatory fires (aerial bombing, artillery, and mortars) but they can also be created purposely by defenders to block avenues of approach by partially or completely destroying buildings using demolitions and fires or simply moving existing rubble.
From September to December 1943 Wehrmacht engineers in Ortona, Italy extensively rubbled the buildings to support the German defense of the city. They blew down corners of houses, entire houses, or even lines of houses to create rubble piles up to fifteen feet high, which were then liberally sown with mines and booby traps. This rubble blocked narrower, ox cart–width secondary streets to force the attacking Canadians down the main thoroughfare and into the main German defensive area. It also made it nearly impossible for supporting tanks to climb over the piles or maneuver to support the dismounted infantry and engineers, and even blocked Canadian observation down the roads.
Modern cities often have existing concrete barriers for vehicle checkpoints or infrastructure protection. These barriers offer ready-made field fortifications. Concrete reinforced with steel rebar is an extremely difficult obstacle to reduce in combat. Concrete barriers can range in size from three-foot-tall, two-ton vehicle barriers used across the world to twelve-foot-tall, six-ton wall segments used by the United States and other militaries in Iraq and Afghanistan.
ISIS fighters used concrete barriers such as T-walls left behind by coalition forces for their defense of the city of Mosul, Iraq in late 2016 and 2017. They used trucks and cranes to move and then pile the barriers on the outskirts of the city. The obstacle numbers and composition required the coalition to take ten-week training courses on combined arms breaching and then use an extensive amount of armored vehicles that included sixty up-armored bulldozers to breach the barriers themselves.
Interior Building Heavy Weapon Systems Positions
Defenders must maximize and protect their critical capabilities. Large weapons can be disassembled and reassembled on the higher floor of a building to provide superior lines of sight and angles of fire. This also creates bunker-like protection to the defender’s most casualty-producing weapons.
At the Battle of Manila, Philippines in 1945, Japanese naval defense forces removed antiaircraft and naval guns from their destroyed ships in Manila Bay and put them in pillboxes and strongpoints across the city. At the Battle of Ortona, the German defenders disassembled two antitank guns and reassembled them on the second floors of two buildings in Piazza Plebiscito, allowing them to destroy two Sherman tanks when they entered the square. It took several hours for the Canadians to bring in more resources to eventually destroy these two antitank gun positions.
Wood, Tin, Tarpaulins or Cloth Sheet Coverings
In the contemporary operational environment, it is becoming increasingly difficult to remain concealed or to conduct deception operations due to the proliferation of aerial reconnaissance assets. Urban defenders must now develop creative ways to hide obstacles, weapon systems, battle positions, and personnel from aerial observation or they will easily be destroyed long before the attacker reaches the main battle area.
There are simple solutions to urban concealment that do not need to be high tech. Civilians in Aleppo, Syria strung forty-foot-high sheets between buildings to reduce sniper attacks while ISIS, as part of its defensive plan in 2017, also placed cloth, metal, or tarpaulins between buildings in Raqqa, Syria to stymie coalition aerial assets. These simple camouflage techniques are the urban operations equivalent of attaching trees and foliage to vehicles in wooded terrain.
Mouseholes and Tunnels
Streets and alleyways in urban warfare can become death traps for both attackers and defenders. The defenders should seek to remain hidden before and during their operation to increase their survivability. The tactic of using mouseholes—holes created in interior and exterior walls of buildings that allow soldiers to move through the exterior walls and interior spaces of buildings—is without question one of the most dominant recurring defense techniques found in urban warfare history. Holes can be made manually with sledgehammers and other tools or with explosives. Tunnels and subterranean spaces can be created between battle positions and when there is an existing underground network, it should be maximized for force protection and mobility.
ISIS fighters in the 2017 Battle of Marawi in the Philippines used mouseholes and tunnels under and through houses to enable movement to and from battle positions and to move to alternate position if they were at risk of being overrun. The mouseholes and tunnels also allowed militants to escape massive aerial bombardments and maneuver against Philippine military forces, ultimately contributing to the amount of collateral damage required to retake the city. During the 1945 the Battle of Berlin, German soldiers proved adept at using the city’s extensive underground transportation, sewage, and other infrastructure networks. The tunnels were used to care for wounded, maintain lines of communication, shelter noncombatants, and conduct attacks. One Soviet commander, Marshal Ivan S. Koniev, recalled that the German forces’ “use of the underground structures caused a good deal of trouble. . . . [German soldiers] emerg[ed] from the underground communications [and] fired on motor vehicles, tanks, and gun crews.”
The defense allows a force to pre-position ammunition, medical supplies, water, and rations. Urban terrain provides great advantages for hidden, protected, and concealed pre-positioned supply points to support multiple primary, alternate, and supplementary battle positions. Attacking forces have the major disadvantage because they are forced to bring their resources forward with vehicles or dismounted personnel and require resources to protect lines of communications to support resupply traffic.
The Germans at the Battle of Ortona had neatly stacked rifle magazines resting on windowsills, along with boxes of grenades and piles of antitank mines in pre-selected rooms, thus allowing them to be unconcerned about the burden of carrying all their required supplies with them as they fought and moved between positions. Japanese naval defense forces preparing for the attack of the US 6th Army at the Battle of Manila put caches in sewers to support their extensive network of battle positions.
Rapidly Emplaced Hasty Obstacles
The urban environment offers a multitude of large objects that allow defending forces the ability to create obstacles both inside and outside of buildings. Vehicles can be repositioned to block streets, furniture can be thrown into staircases, and concertina wire and remotely detonated explosive devices can be added to hinder easy movement between floors and into entryways of buildings. Concrete barriers, cars, buses, construction vehicles, dumpsters, furniture, and tires can be moved into streets and flipped over to channel, divert, or halt enemy armored fighting vehicles or dismounted personnel.
During a significant battle in Sadr City, Iraq on April 4, 2004, Mahdi militiamen and their sympathizers rapidly constructed hasty obstacles made of refrigerators, vehicle engine blocks and axles, rolls of concertina wire, wooden furniture, heaps of burning trash, and rotting meat that stopped American HMMWVs, infantry fighting vehicles, and at times even M1 Abrams tanks. At the 1950 Battle of Seoul, North Koreans made barricades of sandbags, vehicles, debris, and anything else they could get their hands on. The barricades were used to block roads, protect strongpoints, and establish an overall barricade defense system with some obstacles so strong it took UN forces days to clear them.
Hit-and-Run, Antiarmor Ambushes
If the enemy chooses a single axis of advance or if the terrain and defense plan successfully channel the attacker down main roads, the use of mobile antiarmor ambushes has historically shown great success. The use of both static and mobile positions with clear engagement and disengagement criteria only strengthens an urban defense scheme of maneuver. Small, lightweight, lethal, hit-and-run teams armed with antitank weapons can achieve momentum-stopping effects on enemy forces and attrit attacking forces while the defenders continue to draw them into their main defensive area.
During the 1994–95 First Battle of Grozny, Chechnya, Chechen separatists perfected the use of antiarmor ambushes against Russian conventional forces attempting to seize the city. The rebels used small, nonstandard squads with as few as two men as mobile antitank teams. These elements, armed with only AK-47s, grenades, and RPG-7s or RPG-18s, engaged Russian armored vehicles from either basements or upper stories of buildings, where main tanks and other weapons could not effectively return fire. Once in their trap, ambush teams would strike the vulnerable points of Russian tanks and armored personnel carriers, hit the lead and trail vehicles, quickly withdraw, and then move up the flanks to strike the now paralyzed Russian columns again. Between January 1 and January 3, 1995, the Russian 131st Motorized Rifle Brigade lost 102 of 120 armored vehicles and twenty of twenty-six tanks due to these and other methods. Out of the thirty-one T-80BV tanks sent into Grozny with the 3rd Tank Battalion, 6th Tank Regiment, only one tank survived the battle fully operational.
Snipers are a force multiplier while conducting a defense. The urban environment offers snipers and even minimally trained marksmen thousands of protected hide sites and concealed firing lines, including through multiple buildings. Snipers throughout the history of urban warfare have been a dominating feature due to their ability to cause extreme havoc on attacking forces in urban terrain.
The Battle of Stalingrad epitomizes the use of snipers in urban warfare. While the Russians were on the defensive in Stalingrad in 1942, their snipers proved devastating to German forces. Snipers during the battle became national heroes, tallying hundreds of kills. Famous Soviet snipers, like Vasily Ivanovich Zaitsev, mastered the urban terrain and developed new tactics such as using pipes or old barrels as hide sites and making unimaginable shots. The effectiveness of the snipers had a devastating real and physiological impact on the Germans.
Military theorists and current doctrine are correct: the defense is the strongest form of war, and urban defense even more so. Urban terrain offers incredible resources and advantages for a defending force to cause disproportionate numbers of causalities on an attacking element, cause the attacker to run out of time in the strategic environment, and ultimately bring the momentum of an attack to a screeching halt. This can be achieved only if the defending force properly plans, prepares, and executes an urban defense that maximizes the unique properties of urban terrain. The tactics described in this article have worked across different regions, eras, and battles. They have been tried, tested, and proven successful, and any force that sets out to defend urban terrain in the future would be well served by knowing them and planning to incorporate them into an urban defense.
Colonel (CA) John Spencer is chair of urban warfare studies at the Modern War Institute, codirector of MWI’s Urban Warfare Project, and host of the Urban Warfare Project Podcast. He previously served as a fellow with the chief of staff of the Army’s Strategic Studies Group. He served twenty-five years as an infantry soldier, which included two combat tours in Iraq.
Major Jayson Geroux is an infantry officer with The Royal Canadian Regiment and currently with 1st Canadian Infantry Division Headquarters. He has been involved in urban operations training for two decades, and is a passionate student of urban operations and urban warfare historian. He has participated in, planned, executed, and intensively instructed on urban operations for the past seven years. He has served twenty-six years in the Canadian Armed Forces, which included operational tours to the former Yugoslavia (Bosnia-Herzegovina) and Afghanistan.
The views expressed are those of the authors and do not reflect the official position of the United States Military Academy, Department of the Army, or Department of Defense, or that of any organization with which the authors are affiliated, including 1st Canadian Division Headquarters, the Canadian Armed Forces, and the Canadian Department of National Defence.
Image credit: Spc. Dustin D. Biven, US Army