Polish troops also said they had captured seven al-Qaeda suspects and Karbala law enforcement officials accused the US-supervised interior ministry of short supplying before this week's devastating bombings at a religious festival.

Three Iraqis were killed and at least five wounded in a rocket attack by unknown assailants in southwest Baghdad late Thursday, police and witnesses said.

The target of the attack was not immediately clear, but an

AFP journalist said the rocket exploded about 100 metres (yards) from a US military base.

Violence also dogged the northern city of Mosul, where three policemen and two civilians were killed in a rocket and automatic rifle attack, police said.

Another Iraqi police officer was killed and two others seriously wounded in the northern city of Kirkuk when gunmen attacked their patrol, police said.

A US soldier was also wounded near Baquba, in central Iraq, when a homemade bomb exploded near his convoy.

Earlier, Polish troops said they had arrested seven al-Qaeda suspects since mid-January, including two in the past week, in the countdown to the rampage on the Shiite Muslim holy city during the Ashura pilgrimage.

The Polish military spokesman conceded the US-led coalition had anticipated Tuesday's spectacular bombings, but stuck to a security plan putting Iraqi forces in charge of the city for the major holiday.

Polish Warrant Officer Zbigniew Dabkiewicz said two of the suspects were connected with Jordanian Abu Moussab al-Zarqawi, the US-led coalition's prime suspect the Karbala and Baghdad attacks.

The pair, both Iraqis, were implicated in a December 27 suicide bomb attack in Karbala that killed 19 people, and are now in US custody, he said.

As fears of fresh violence ran high on the eve of the signing of a temporary constitution, Karbala law enforcement officials vented anger at being undermanned ahead of Ashura.

They charged that the interior ministry had failed to meet a request for weapons, cars and radios.

The series of bombings in the city and the capital killed 173 people and wounded 553 others, interim health minister Khdeir Abbas said Thursday, giving an updated toll.

Speaking in Washington, the top US commander in the Middle East opposed the formation of Shiite militias in response to Tuesday's violence, warning that it would be a "destabilizing event."

General John Abizaid's comments before the Senate Armed Services Committee came in response to reports of rising demands by Shiites to protect their communities with militias tied to political parties in the face of escalating attacks targeting civilians.

In Warsaw, NATO Secretary General Jaap de Hoop Scheffer said he would send soldiers to Iraq if Baghdad requested them and that the United Nations should mandate a stabilisation force for the country under sovereign self-rule.

"After the 1st of July, it is up to the sovereign Iraqi government to decide" whether to ask NATO to send troops, he said.

The United States is to formally end the occupation of Iraq and hand over power to a sovereign government on June 30, although it will retain a military presence in the country.

In Madrid, Russian Foreign Minister Igor Ivanov said attacks would continue to rock Iraq until the lingering US-led occupation was wrapped up.

"We believe that the only way to resolve this problem are a political settlement and elections in a sovereign Iraq, issues which are currently being discussed at the United Nations," he said.

The European Commission also warned that security is the key constraint on delivering millions of dollars of aid to Iraq, as it listed its priorities for spending money pledged last year.

In the aftermath of allegations by a former British cabinet minister that London spied on Kofi Annan in the run-up to the Iraq war, the UN Secretary General met Britain's UN representative Emyr Jones Parry.

Initially announced for Wednesday, the meeting was put back 24 hours at Jones Parry's request, said a spokesman.

"You can guess one of the subjects on the agenda," he told reporters.

Back on the ground, US troops in Baghdad are also to begin focusing their mission on extremists, with remnants of the former Iraqi regime becoming an increasingly spent force, Brigadier General Martin Dempsey said.

Operation Iron Promise, to be launched on March 16, will replace Operation Iron Grip, which focused on cells of fighters from the desposed Baath party and those loyal to former president Saddam Hussein.

"The motivation of the enemy is changing from former regime to extremists," Dempsey told reporters.

Dempsey said the Baghdad and Karbala bombings were carefully planned, going off one minute apart.

"It is a level of coordination that we have seen only a few times," Dempsey said, adding that he had seen similar tactics employed in Afghanistan.AFP