And in a new major step toward ending the war, the commander of the Iraqi army's Anbar sector command, who led 16,000 troops with control extending to the Syrian border, surrendered to US forces, an AFP reporter witnessed.

"I am ready to help. Thank you for liberating Iraq and making it stable," Iraqi General Mohammed Jarawi told US Colonel Curtis Potts after signing the surrender in the western Iraqi desert.

"I hope we have a very good friendship with the United States," he said.

But with hardline rhetoric against Iraq's neighbour Syria ratcheting up, sporadic violence flaring in Iraq and the hunt for Iraq's alleged chemical, biological and nuclear arsenal still coming up empty-handed, Washington was shying away from declaring the conflict over.

"I would anticipate that the major combat engagements are over because the major Iraqi units on the ground cease to show coherence," Army Major General Stanley McChrystal, vice director of operations of the Joint Staff, said in Washington Monday.

But Victoria Clarke, the Pentagon spokeswoman, told reporters not to expect a declaration of victory.

US troops seized the last bastion of Iraqi resistance Monday when they took Tikrit -- the hometown of Saddam Hussein -- after gunbattles on the outskirts of the northern town.

The capture of Tikrit meant all the key population centres were under US or British military control.

Only occasional armed opposition remained, though US and British troops were wary of further suicide bomb attacks, after the deaths of eight US soldiers in three blasts since the March 20 start of the war.

In Baghdad, which fell on April 9, and in other cities, the foreign troops were turning their attention from combat to enforcing law and order.

US troops in the capital were conducting joint patrols with Iraqi policemen to clamp down on the looting that erupted in the power vacuum caused when officials in Saddam's regime fled or went into hiding.

The fate of the Iraqi president and his closest lieutenants and family members remained unknown.

US defence officials said that some of the 300,000 US troops deployed to the Gulf region for the war would be repatriated soon.. About 140,000 US and British troops are inside Iraq.

Two US aircraft carriers -- the USS Kitty Hawk and the USS Constellation -- are due to head home from the Gulf as early as this week, and stealth bombers and other warplanes were also due to return.

Some British ships and other units have also started to return home.

McChrystal said: "We will move into a phase where it will be small, albeit sharp fights."

He said fresh US troops scheduled to arrive would be heavily weighted with military police, engineering and civil affairs units, though armoured units would remain.

"There will be a requirement for combat power for some period of time to maintain or to establish that secure and safe environment," he said.

US commanders said four US soldiers were killed Monday, but stressed that accidents, not enemy attacks, were to blame.

Three US soldiers died and three others were wounded when a grenade went off while they were working on a vehicle south of Baghdad, a statement said.

Another soldier died and one was wounded in "an apparent accidental weapons discharge incident in the vicinity of Baghdad International Airport," the US Central Command said.

Added to Pentagon figures given Monday, the number of US soldiers killed in Iraq tallies at least 122. Of those, 105 fell to enemy or friendly fire.

With the threat level in Iraq on the ebb, Washington and London have been turning their joint attention to Syria, raising speculation that Damascus may be next on the coalition hit-list.

US President George W. Bush's spokesman, Ari Fleischer, accused Syria of being a "terrorist state", while US Defence Secretary Donald Rumsfeld said Syria had carried out a chemical weapons test "over the past 12, 15 months."

US and British officials have also accused Damascus of recently cooperating with Saddam Hussein and of taking in fleeing members of his regime.

Syria, which strongly denies the allegations, has invited arms inspectors to check.

SPACE.WIRE