Kurdish guerrillas have begun to pull back from the northern Iraqi city of Kirkuk which they seized from Saddam Hussein's regime on Thursday. US invasion forces are increasing their presence to establish control in the city which is a centre of the oil industry in the north. Correspondents say the moves are vital to pacify Turkey which borders northern Iraq and which opposes any moves to create an independent Kurdish state in the area. The US-led coalition is also trying to restore calm in cities wracked by violence and looting since the regime lost power.

The BBC's Paul Wood in Baghdad reports violence is now crossing the religious divide, with Shia Muslims fighting gun battles with their Sunni neighbours throughout the capital.

Border Build-Up

Troops are moving towards Saddam Hussein's home town of Tikrit, one of the few cities still outside their control.

They have also begun taking control of the northern city of Mosul which was abandoned by Iraqi troops on Friday.

The Americans have imposed a curfew there and told Kurdish militia to stay on the outskirts.

The BBC's Dumeetha Luthra in Kirkuk says groups of the peshmerga fighters are leaving the city, three days after their arrival caused a political storm.

Thousands of Kurdish guerrillas flooded in as the Iraqi army abandoned Kirkuk.

Turkey demanded that the US take control and has sent monitors to satisfy itself that the Kurds are not establishing a power base.

Tens of thousands of Turkish soldiers remain stationed on the Iraqi border but our correspondents say the hope is that tensions will ease.

US troops are setting up a base at the military airport in Kirkuk and reinforcements are expected.

Lawlessness

The centre of Kirkuk is largely peaceful amid the growing American presence, though there has been looting on the outskirts of the city.

Lawlessness has been more of a problem in Mosul and Baghdad. The BBC's Andrew Gilligan in the Iraqi capital says violence is widespread.

Looters are now hitting ordinary civilian homes and businesses after running out of targets of the former regime, he says.

People - even hospital staff - are now armed to protect themselves and their property and some thieves have been beaten to death on the streets, our correspondent adds.

The International Committee of the Red Cross says it is profoundly alarmed by the situation in Baghdad, which it says is verging on anarchy.

The organisation, reminding the US and Britain of their legal responsibility to protect civilians and essential services, says looting has left the capital with virtually no functioning hospitals.

US troops in Baghdad have called on the city's police to return to work and the US Government says it will send 1,200 law and order experts to Iraq to advise on the establishment of a new police force.

But US Defence Secretary Donald Rumsfeld denied Iraq was falling into chaos.

"Free people are free to make mistakes and commit crimes and do bad things," he told reporters.

"While no-one condones looting, on the other hand one can understand the pent-up feeling that may result from decades of repression," he added.

In other developments:

·Violence continues in the southern city of Basra, where British soldiers shot and killed five men as they tried to rob a bank .

·Tikrit was pounded by air strikes overnight with US-led forces targeting what is believed to be the last major stronghold of loyalists to Saddam Hussein .

·A US delegation plans to meet Iraqi opposition leaders in Nasiriya on Tuesday to discuss an interim government .

·American troops have been issued with playing cards showing 55 leaders of the Iraqi regime who will be "pursued, killed or captured", according to commanders. Most Iraqi officials have disappeared since US forces took control of the centre of Baghdad .

PHOTO CAPTION

Guerrillas took control of Kirkuk when Iraqi forces disappeared