20110418
reuters

TUNIS/BERLIN (Reuters) - Battling tanks and snipers in Misrata's streets, the rebels holding the city are exploiting a defender's natural advantage in urban warfare to survive a two-month onslaught by better-armed government troops.

Blocking a main street with sand-filled trucks and trying to isolate and flush out gunmen loyal to Libyan leader Muammar Gaddafi firing at them from rooftops, insurgents are waging a desperate fight to cling on to their last major western bastion.

But Misrata's fate will likely depend on whether they can prevent their foes from seizing or denying access to its port -- a lifeline for trapped civilians and for food and medical aid, as well as a possible way to bring in arms and ammunition.

"Control of the port is essential because without that they would be truly cut off, they would fold, they would not be able to withstand the siege," Shashank Joshi, analyst at Britain's Royal United Service Institute, said.

Footage of rag-tag rebels with rocket-propelled grenades and automatic rifles crouching among crumbling buildings and launching hit-and-run attacks evoke images of other city sieges -- such as the Serb encirclement of Sarajevo in the early 1990s.

But analysts say they have a much-needed edge in fighting in built-up areas on their home turf. They know the terrain better than their adversaries, who may also experience difficulties in using their heavy weaponry to maximum effect.

"Even the most efficient and professional troops in the world -- like the Americans, the British, who have been in Iraq for example -- have found that in urban fighting the advantage is always on the defender," said military analyst Paul Beaver.

Insurgents can use their local knowledge to spring ambushes, and the only way to seize Misrata would be to start levelling it, as the Soviets did in Berlin at the end of World War Two.