The INTERNATIONAL INSTITUTE FOR STRATEGIC STUDIES

FIGHTING in cities has always been a difficult and unpleasant task for modern armies. The nature of urban terrain has cancelled out many of their advantages in terms of air power, armoured forces and superior communications.

Even the effectiveness of heavy artillery is limited, given that ruined buildings can provide adequate shelter for determined defenders. As a result, some American studies have suggested that the US military should avoid urban operations altogether -- but the vast growth and spread of the world's cities make this hardly feasible.

Around 70 per cent of the global population will live in urban areas by 2020. Cities are bound to be a key battlefield of the future.

Capturing urban areas has required large numbers of infantry troops in the past.

Even when these forces have been courageous, highly motivated and adept at methodically clearing rooms and buildings of enemy personnel, they have usually suffered heavy casualties and inflicted many civilian deaths.

The challenge to Nato forces has increased, following the decision by most member states, including the US, to reduce their militaries to the point where they can no longer realistically expect to fight in cities for long periods with large numbers of dismounted infantry troops.

A megalopolis, such as Mexico City, with a population of 10 to 20 million, could easily absorb entire armies -- as Pakistan has found in its efforts to contain ethnic violence in Karachi.

The other historical alternative -- besieging a city and trying to starve its population into surrender -- is also probably no longer feasible politically.

Another complicating factor in Western planning for urban operations is that, for the foreseeable future, most such operations are likely to be part of peacekeeping or policing missions, and not of wars per se.

While peacekeeping operations can turn easily into serious battles, the rules governing the employment of lethal force are supposed to be much stricter than in warfare, the mission's objectives and technology required quite different.

In Northern Ireland or Bosnia, for example, the use of massive fire-power would be inappropriate and utterly counter-productive.

CONTROL PROBLEMS

MOST of the difficulties of fighting in cities have been apparent to soldiers for hundreds or even thousands of years. One problem is command and control.

British troops in Northern Ireland in the 1970s, and Russian forces in Chechnya in 1994 to 1996, both found that short-range radio communication was often blocked by buildings.

Consequently, they re-learnt the ancient lesson that urban warfare limits the role of senior commanders, and puts greater responsibility on junior and non-commissioned officers, as well as on the individual soldier.

In the past, the question of civilian casualties was rarely a consideration in urban warfare. The need to limit non-military losses was fast forgotten by US forces in Mogadishu in 1993 when they came under heavy attack. So, at least 500 civilians died, compared to 18 US soldiers, a ratio of some 30:1.

When faced with the danger of an unseen enemy, the response of ordinary soldiers has usually been to throw a grenade first and ask questions later. If the room happened to be occupied only by civilians, that was too bad.

In addition, modern armies have usually advanced into well-defended cities backed by heavy air and artillery barrages.

Western humanitarian concerns, however, are making such casualties and gross physical destruction increasingly unacceptable.

This constraint is even greater when retaining local support is a top political and military priority.

STRATEGIES

THE US armed forces' solution to the urban-warfare problem is to exploit new technology and attempt to develop the same capability for high-speed operations that it possesses in open terrain -- although this hope has been derided as illusory by some military critics.

Technological superiority -- demonstrated during the 1991 Gulf War -- provides contemporary Western, and especially US, forces with almost insuperable advantages in open warfare.

These benefits are comparable to those held by Western armies over "traditional opponents" in the 19th century. And as in that era, one enemy response will be to try to choose the best terrain for battles -- which now means, above all, cities.

During the Hungarian Revolution in October 1956, rebel fighters covered Budapest streets with soapy water to slow Soviet tanks, and then showered them with Molotov cocktails. Without supporting infantry, the tanks were easy targets.

To regain control, the Soviet Union had to commit about 16 combined armoured and infantry divisions -- more than the US army has today.

In January 1995, Chechen defenders allowed Russian armoured columns to enter Grozny, before cutting them off and attacking them from roof-tops with armour-piercing rocket-propelled grenades.

The rebels destroyed 102 of 120 armoured personnel carriers and 20 out of 26 tanks.

Victory was made possible in part by the unwillingness of Russian soldiers to leave the (illusory) shelter of their armour and fight in the open. The Chechen experience demonstrates that adequate dismounted infantry forces must be available to protect armoured units when they enter an urban environment. The US military's future urban operational concept thus recommends the creation and use of relatively small units equipped with high-technology systems.

When necessary, high-speed armoured vehicles will move forces into or through urban areas to defeat pockets of strong opposition.

To locate and destroy enemy positions, while minimising US casualties, will require heavy reliance on unmanned aerial vehicles, unmanned ground vehicles (UGVs), a wide variety of sensors and an improved "urban version" of the Land Warrior System (LWS).

The US military's new attention to urban warfare in the 1990s was initiated by the Marine Corps, which sought to make the field its preserve and launched in September 1997 the "Urban Warrior" series of experiments and exercises.

These trials will culminate with an "invasion" of Oakland, California, in April. The Corps policy inspired the army to incorporate urban-warfare planning into its "Army After Next" study.

The open rivalry between the two services led to criticisms that they were unnecessarily and expensively duplicating exercises and research and development of new weapon systems.

Partly in response, they formed the joint Advanced Concept Technology Demonstration (ACTD).

The project -- which is supposed to provide near-term solutions to urban-warfare problems -- is examining new weapon systems that may be developed early in the next century.

Units using technologies adopted under ACTD will conduct a large-scale urban exercise in September to demonstrate the benefits of these systems.

All urban-warfare studies so far suggest that the most important technologies needed to improve US capabilities in this field are communications, robotics and non-line-of-sight munitions.

Forces involved in urban warfare must have "hands free" non-line-of-sight communications and computer positioning systems that will give an accurate sense of location. These technologies must also connect the soldier to precision-engagement weapons within and outside the urban area.

The most critical component of the LWS, where urban warfare is concerned, is the Integrated Helmet Assembly Sub-system (IHAS).

It enables the soldier to view computer-generated graphical data, digital maps and intelligence, as well as troop locations and imagery from a Thermal Weapon Sight and video camera.

The IHAS permits a soldier to see around a corner, locate a target and fire a weapon without being exposed, as well as engage targets in darkness.

There is a serious risk, however, that this range of complex equipment will overwhelm individual infantrymen and put them in greater danger.

The British army's experience of armoured warfare, for example, has been that even sophisticated optics are insufficient, and courageous troops prefer to risk exposure to see what is happening.

To minimise military casualties and the importance of individual courage and morale, the US thinking is focused increasingly on robotic devices. But there is a serious risk that, unless equipped with recognition devices -- which are far from development -- robots will kill every living thing in their path, including allied soldiers without the necessary electronic identification.

Such weapons, however, are still several years from full development. These expensive projects also have to compete for resources with the US military's intensive effort to modernise its heavy armoured forces.

As a result, it will be a long time before US weaponry catches up with urban-warfare theory. In the meantime, further bloody urban debacles remain a strong possibility.

CHALLENGES

REGARDLESS of the advantages that can be achieved through the development and use of high-technology forces, large numbers of traditional land units will continue to be required for many future urban operations.

As a result, there is an informal consensus among many US military officers that, for some time to come, allied forces should ideally be employed on the ground in urban areas, while US troops provide long-distance, advanced firepower.

But being used as "cannon fodder" in this way would hardly be popular with the allies concerned.

[The International Institute for Strategic Studies is a London-based think-tank. This article is part of a series on strategic issues it published.]