Fighting In The Canyons

This is an article published in our April/May 2017 Compendium.

MOUT requires armies to maintain strong autonomy as small units will need divide to clear urban areas, and at the CENZUB soldiers learn to work in small groups. (Alix Valenti)

The key characteristic of MOUT (Military Operations in Urban Terrain) is that urban terrain, in all its complexities, has altered the balance of power as victory no longer necessarily belongs to the belligerent with the most deadly and technologically-advanced capabilities.

According to Colonel Pierre Santoni, the French Army’s former commanding officer for its Centre d’Entraînement en Zone Urbaine (Urban Zone Training Centre) located in northeast France, intrinsic to prevailing in MOUT is, first and foremost, a matter of having or acquiring as deep an understanding of the urban environment as possible. As such, a determined insurgent group which knows the urban environment really well will be able to fight on equal footing with soldiers equipped with the best capabilities but little knowledge of the terrain.

After spending decades decreasing their military personnel: A study by the consultancy firm Roland Berger published in 2015 stated that over the past decade NATO (North Atlantic Treaty Organisation) personnel levels had dropped by one third, and investing in advanced technologies, Western armies engaging in MOUT are coming to terms with the fact that: “Aside from technology, the number and quality of combatants and (commanders) will also be deciding factors (in MOUT),” as stated in Frédéric Chamaud’s and Col. Santoni’s 2016 book L’Ultime Champ de Bataille: Combattre et Vaincre en Ville (‘The Ultimate Battlefield: Fighting and Winning in the City’). Adequate training and careful strategic and tactical planning is therefore intrinsic to increasing the chances of success during MOUT.

Tunnel Effect

The first key characteristic of the urban environment is the fact that it is very closed-up. The multitude of streets, small alleyways, street corners and high-rise buildings provide many possibilities for an ambush by an adversary. This can be very disorienting for a soldier that does not know the area well or whom has not been prepared for it. An essay published in 2012 in the French magazine Histoire et Strategie (History and Strategy) entitled Les Trois Characteristiques des Operations Urbaines (The Three Characteristics of Urban Operations) explained that: “The sense of isolation incurred by the presence of buildings limits units’ movements, channelling them into streets and other passages, allowing the adversary in a defensive position to predict to a certain extent their movements.”

In their book, Mr. Chamaud and Col. Santoni call this “the tunnel effect,” arguing that “streets kill.”

The ‘tunnel effect’ has a particularly strong psychological effect on individual soldiers, who suddenly feels that they could be an easy target at any moment. The operational consequences of a soldier that tires more quickly, due to the stressful environment, are key concerns to take into account in training as well as during the operational and tactical preparation for a MOUT action.

Finally, it is often the case that the streets are too small to facilitate the manoeuvring of armoured vehicles, making it more difficult for the infantry to rely on the support of these vehicles for additional protection. Indeed, the firepower normally afforded by these vehicles facilitates the targeting and elimination of the adversary in the locale surrounding the units. Without such support, the same units are even more exposed to potential threats and surprise attacks. Nevertheless, contemporary rules of engagement which have, since the end of the Cold War, required NATO to minimise civilian casualties and damage to civilian infrastructure can also restrict the application of such force during MOUT.

3D vision

MOUT actions are further complicated by the three-dimensionality of the urban environment. It is no longer only a matter of what individual soldiers can see in their field of vision, but it is also, and perhaps even more importantly, a matter of what lies within, above or beneath a building. As the experience of Sarajevo (please see Cities In Conflict) revealed, snipers can hide anywhere in an urban environment, starting from behind a window all the way up to the rooftop of a building. Similarly, adversaries can hide in the numerous underground passages such as sewage systems and underground transportation that comprise the fabric of the urban environment.

The equipment currently at the disposal of many armies around the world is yet unable to fully assist soldiers in the task of preparing for such complex environments. Maps, which soldiers learn to use during their training, are only bi-dimensional. They do not provide any information regarding the height of buildings surrounding the street a unit intends to take, for example, nor do they offer a reading of the potential presence of underground passages. Yet, underground passages quickly become a key asset for those who know of their existence. As indicated in the Marine Corps’ doctrinal publication Military Operations on Urbanised Terrain published in May 2016: “Both attacker and defender can use subterranean avenues to manoeuvre to the rear or the flanks of an enemy. These avenues also facilitate the conduct of ambushes, counterattacks and infiltrations.” For instance, during the Battle of Aachen, which occurred in and around the German city of Aachen in the west of the country fought between 2 October 1944 and 21 October 1944, German troops regularly used underground passages to appear behind US soldiers and engage them without difficulty. Such tunnels can also be used for the storage of ammunition, thus creating a significant advantage against opposing forces which may face significant logistical challenges in this regard when trying to re-supply their forces conventionally during MOUT.


Unlike cities in the pre-industrialised world, today’s urban areas are complex environments consisting of a combination of different areas. The city core, which is common to all urban areas, varies in its fabric according to countries’ levels of development and architectural history, but is similar across the globe in that it is very dense. The commercial ribbons are the city streets that are predominantly lined with shops, restaurants and businesses. Although, again, this varies from county to country, commercial ribbons are usually built around wider streets in order to allow large influxes of people and to facilitate the circulation of delivery vehicles. Beyond the city core lies the core periphery which consists of streets, of varying widths, lined predominantly with residential buildings. Outside the core periphery is the residential sprawl which often takes the form of vast poor and very dense areas in developing countries, whereas in a developed country this sprawl can simply represent a series of new residential developments built to accommodate a rising population. Last but not least, the outlying industrial areas generally consist of clusters of industrial buildings.

French Army’s CENZUB installation
Cities are complex environments including different areas presenting different urban fabrics, and at the French Army’s CENZUB installation, the village of Jeoffrecourt includes a core periphery. (Alix Valenti)

According to the Marine Corps’ MOUT doctrinal guidance cited above: “each of the urban area’s regions has distinctive characteristics that may weight heavily in planning for MOUT.” Dense areas, such as city cores, are generally more prone to provoking the ‘tunnel effect’ (see above), and are much more complicated to access for support vehicles such as main battle tanks and armoured vehicles. Commercial ribbons, core periphery and residential sprawl are more conducive to the circulation of these vehicles, and can often represent ideal avenues for approaching the city core and progressively securing an urban space. Outlying industrial areas, however, can become a substantial problem due to the fact that they often include buildings with dangerous materials such as chemicals or gas. The risks represented by these outlying industrial areas are known as ‘Risks Other Than Attacks’ (ROTA), according to the essay Les Trois Characteristiques des Operations Urbaines (see above).

Operational Issues

At the operational level, the characteristics of the urban environment outlined above have one key consequence: MOUT implies combined arms manoeuvre. A number of confidential sources whom spoke to Armada during the preparation of this article highlighted some important considerations to this end. Arguably, the most common form combined arms manoeuvre involves the close cooperation of infantry and armour. The use of main battle tanks and armoured vehicles in a city, provided there are no restrictions to their circulation (such as street width or bridge weight limits), provides the infantry with an assault weapon to be used against buildings or strong points where adversaries are known to be hiding. However, Col. Santoni warned in an interview with Armada that: “armoured vehicles and tanks need protection in urban areas.” Their field of vision is limited to the ground, and the unit inside cannot afford to come out of the vehicle to see what is going on. As such, these vehicles are vulnerable to munitions coming from any angle in the city, as well as to any threats emanating from underground passages. Thus, the role of the infantry is to protect these vehicles. Key to this partnership is the quality of the communications between the vehicle and their accompanying dismounted infantry unit: the latter needs to be able to quickly and efficiently communicate to the former precise coordinates for the direction of fires.

exercise at the CENZUB
During an exercise at the CENZUB: armoured vehicles provide the infantry with an assault weapon while the infantry provides mutual protection for the vehicle. (Alix Valenti)

During MOUT, combined arms manoeuvre may also include aviation. Close Air Support (CAS) provides infantry and armour with additional striking power where vehicles cannot reach, or where it is too dangerous for infantry to venture. This requires highly trained Joint Terminal Air Controllers (JTACs) that communicate with the different units to direct aerial fires.

soldiers learn to evacuate
MOUT incur more wounded than military operations in open spaces, and during their training soldiers learn to evacuate casualties quickly and efficiently. (Alix Valenti)

Operationally, any MOUT planning needs to carefully outline a plan regarding logistics. Before entering potentially confined urban zones, it is vital to determine at least one route that can be easily protected for use as a logistics corridor, as well as to facilitate the evacuation of wounded and the regular rotation of assault units. The evacuation of wounded troops is indeed also a key to successful MOUT because, as a French military source said: “MOUT operations incur more dead and wounded than operations in any other terrain, therefore being able to evacuate and treat wounded soldiers as efficiently as possible means they can quickly go back to the battlefield; failure to do so means fighting in one of the most complex environments with a dwindling army”.

Last but not least, MOUT are demanding in terms of personnel and require that commanders at all echelons be well trained to work separately and to coordinate combined arms manoeuvre. When attempting to stabilise the situation in, or when reclaiming, a city armies can no longer work in big formations; rather the nature of the environment dictates that they divide into smaller units in order to approach from different axes and spread to secure different buildings and areas. As indicated by the French military source: “The degree of autonomy imposed by the numerous micro-theatres of the battleground will result in squad, platoon and company commanders being left to make decisions for themselves.”

strong autonomy as small units
MOUT requires armies to maintain strong autonomy as small units will need divide to clear urban areas, and at the CENZUB soldiers learn to work in small groups. (Alix Valenti)

Tactical Implications

At the tactical level securing a city is extremely time, and ammunition, consuming. The possibility of a new threat in every new street, corner and building means that units moving into a city have to go through these buildings one-by-one, and secure them floor-by-floor and room-by-room. According to Sean Page, senior associate at Avascent, a consultancy based in Washington DC: “Individual soldiers need to learn how to move in a city environment, where threats are all around and tactical options are very limited; as a result, going through compounds rather than streets is generally safer.” This translates into a large number of rounds being expended either against the adversary or in the room where there is a suspicion that an adversary might be present to ensure that it is cleared.

The chaos of MOUT also has the potential to incur casualties in the midst of operations, whether they are friendly forces or civilians. This requires that, to the extent possible, the organisation of MOUT also includes evacuating civilians as fast as possible prior to commencing operations. The rules of engagement for military operations have become very strict regarding civilian casualties. The Marine Corps’ MOUT doctrinal guidance requires: “Minimising civilian casualties and/or collateral destruction in order to: avoid alienation of the local population; reduce the risk of adverse world or domestic opinion; preserving facilities for future use; and, preserving cultural facilities and grounds.” Similarly, the chaos of MOUT places a premium on detecting and identifying friendly forces. While this is usually done through the development of new technologies such as Blue Force Tracking (BFT) which depicts friendly (Blue) and hostile (Red) forces, the past decade has seen a proliferation of BFT systems such as those offered by ViaSat namely its Blue Force Tracking-2 system used by the US Army and Marine Corps; Elbit Systems, which is fulfilling the Australian Army’s BGC3 BFT requirement and Thales which provides a BFT capability as an integral part of its NORMANS (Norwegian Modular Arctic Network Soldier) infantry soldier system which is currently equipping the Norwegian Army. Nevertheless, the three-dimensional characteristic of urban environments remains particularly difficult to represent on handheld or vehicle-mounted BFT devices. As Gen. Bouquin asked: “how do BFT devices cope with showing friendly forces present on different floors in a building?”

Last but not least, tactical communications, which are key to any military operation, can be extremely disrupted in urban environments. Both Very High Frequency (VHF) and Ultra High Frequency (UHF) communications, which use a frequency band of 30 megahertz to three gigahertz, are limited to line of site ranges. So called ‘Urban Canyons’ where streets are flanked by high rise buildings can block the line-of-sight radio transmissions employed by VHF and UHF radios. Inside buildings, such radios can have their transmissions limited by the thickness of walls or floors, while a crowded electromagnetic spectrum, which may also include radio and television stations, civilian radio communications (such as those used by taxis or the emergency services) not to mention cell phone traffic, may also have an adverse effect on the ability of VHF and UHF tactical radios to work as desired. Nevertheless, mobile ad hoc networking, by which tactical radio transmissions ‘hop’ from one transceiver, within the transmitting radio’s line-of-sight to another until reaching the transmissions’ intended recipient, in much the same way as a frog jumps from one lily pad to another across a pond, provide one means of meeting the communications challenges presented by the urban canyon. Similarly, the advent of the US armed forces Mobile User Objective System (MUOS), a UHF satellite communications constellation being developed by Lockheed Martin on behalf of the US Navy, provides a means by which UHF radio transmissions can be transmitted into space to bounce of one of the four MUOS spacecraft in geostationary orbit to reach their recipients; once again avoiding the physical restrictions imposed by the urban canyon. That said, despite some of the potential communications solutions offered for MOUT, writ large, commanders still need to have a very high level of autonomy during operations, as well as trust in the original planning of their MOUT action, while individual soldiers need to trust both direct orders and their instincts.

by Dr. Alix Valenti