US-led forces were involved in fierce gunbattles today in Fallujah as rebel fighters trapped in southern part of the city tried to break out of a security cordon.
US forces had pushed deeper into the southern reaches of the Iraqi city, backed by aircraft and helicopters, as they sought to corner rebels.
Most of the rebels still fighting in Fallujah are believed to have fallen back to southern districts ahead of the advancing US and Iraqi forces, although fierce clashes were reported in the west of the city around the public market.
US officers said the majority of the rebel mortar and machine-gun fire was directed at US military units forming a cordon around the city to prevent rebels from slipping away. US officers said that suggested the insurgents were trying to break out of Fallujah rather than defend it.
With insurgent fire cover from nearby buildings, three to four dozen militants tried to break out of the security cordon to the south and east of the city last night but were pushed back by US troops, the military said.
US forces are also positioned to the west near key bridges, blocking rebels from crossing the Euphrates River with patrol boats.
The four-day Fallujah offensive has killed an estimated 600 rebel fighters.
About 22 US and Iraqi troops have been killed and about 170 have been wounded in the battle.
The Iraqi Red Crescent Society said it had asked US forces and Iraq's interim government to let them deliver relief goods to Fallujah and send medics there. But it said it had received no reply.
Aid agencies have called on US forces and the Iraqi government to allow them to deliver food, medicine and water to Fallujah and said four days of intense fighting had turned the city into a "big disaster".