PRIME Minister Tony Blair has paid tribute to the six Royal Military Police soldiers killed in Iraq.He told MPs yesterday they had been doing an "extraordinary and heroic job", adding "the whole country and their families can be immensely proud of them'.

Reports by Sharon Asplin and Juliette Maxam

PRIME Minister Tony Blair has paid tribute to the six Royal Military Police soldiers killed in Iraq.

He told MPs yesterday they had been doing an "extraordinary and heroic job", adding "the whole country and their families can be immensely proud of them'.

Mr Blair was commenting as details of the events leading to the murder of the six soldiers on Tuesday began to emerge.

According to local people, the Red Caps, from the Colchester-based 156 Provost Company, were killed by Iraqi civilians after they opened fire on a demonstration against the Allies in the town of Majar al-Kabir, north of Iraq's second city Basra.

The attack, the biggest single combat loss suffered by British forces since the first Gulf War, prompted the Government to raise the prospect of sending thousands more troops to Iraq.

British forces gave yesterday civilian leaders in the town 48 hours to hand over the gunmen responsible for the attack.

British military spokesman Lieutenant-Colonel Ronnie McCourt said the attack was unprovoked, adding: "It was murder.'

But Abbas Faddhel, an Iraqi policeman in the town, said the British soldiers shot dead four civilians during Tuesday's protest outside the mayor's office.

The demonstrators had apparently been protesting against heavy-handed British tactics during a sweep of the area for weapons.

One witness said British soldiers first fired rubber bullets - and then live ammunition - into the crowd.

Furious residents killed two Britons at the scene of the protest before chasing four others into a nearby police station and killing them after a two-hour gun battle, said Mr Faddhel.

Abu Zahraa, a 30-year-old market trader in Majar, claimed civilians had been killed by British soldiers during the demonstration.

Mr Zahraa and another witness, who would not be named, said the British troops had retreated to the local police station when they were attacked.

Angry townspeople then went to their homes to fetch assault rifles, returned to the station and attacked the besieged British soldiers, all of whom were killed, the witnesses said.

One British soldier was shot dead in the doorway of the building and the other three were killed after Iraqi gunmen stormed the station, said Salam Mohammed, a 30-year-old member of a municipal security force.

A British military spokesman, Capt Adam Marchant-Wincott, said he could not confirm the witness accounts.

But he said it was possible there had been an agreement between British forces and the local police letting the locals take over security for the town.

He could not say whether the British forces had fired at the demonstrators, but added they would have done so only if their lives had been threatened.

Mr Faddhel said that there were about two dozen Iraqi policemen at the station who fled through a window during the gun battle.

He added they had pleaded with the British military police to flee with them, but the British had insisted on staying.

The building bore the scars of a fierce gun battle. Its walls were riddled with bullet holes, and broken glass and dried blood stains covered the floor.

The clash raised fears that violence is spreading to formerly calm regions of Iraq, despite assurances by U.S. officials that they are mopping up resistance.

Majar al-Kabir is a mostly Shiite town about 180 miles south-east of Baghdad and just south of Amarah.

Defence Secretary Geoff Hoon said yesterday thousands more British troops could be sent to Iraq following the killings.

An urgent review of troop numbers and tactics was under way, following the deaths of the Military Police soldiers, who were in the area training local Iraqi police personnel.

Mr Hoon said: "Obviously, depending on the results of that review, we have more troops should that be required. We have significant forces available should it be necessary.'

Asked whether up to 5,000 more troops might be sent, Mr Hoon added: "It is certainly not beyond the bounds of possibility.'

He continued: "We have had remarkable success across southern Iraq. We have not had this kind of incident before. I'm not in any way being complacent about it. It was a dreadful day yesterday.

"But at the same time it is important to recognise that this is not typical, it is not widespread, it is not something we have seen in any other part of our area of operation.'

U.S. troops have come under repeated attack, but the UK force, stationed in the south, had not been struck since May 1.

Mr Hoon insisted thought had been given to an "exit strategy" for British troops in Iraq, but said withdrawal appeared a long way off.

He added: "Central to any exit strategy in this kind of situation is the ability to train local people, to develop local security arrangements, so that the people of Iraq as soon as possible become responsible for their own affairs and their own security. There is both a political dimension to that as well as a security dimension.'

Meanwhile, the commander of the British land forces in the Iraq war acknowledged the troops had taken a risk switching their helmets for berets so soon after the warfighting had finished.

Major General Robin Brims told the Commons Defence Committee the decision when to make the change over had been taken by individual unit commanders on the ground - sometimes sergeants or corporals.

"I didn't give orders. I left it to the local commanders as they saw fit. There is a risk in it. I think it is a risk worth taking. I think those judgments were well-exercised by everyone," he said.

The British were keen in the days following the fall of Basra to be seen patrolling without their helmets as part of the "hearts and minds' campaign to win over the local population.