BAGHDAD - A string of car bombings in quick succession killed at least 17 people in a Shiite district of Baghdad yesterday, as US Defence Secretary Donald Rumsfeld refused to set a deadline for a troop withdrawal.

Rumsfeld assured lawmakers in Congress that US troops were defeating the stubborn insurgency and rejected calls that the Pentagon scale back the military presence in Iraq.

"Any who say that we've lost this war, or that we're losing this war, are wrong. We are not," said Rumsfeld.

Rumsfeld noted that some in Congress had suggested that deadlines be set for a withdrawal, but he rejected that idea as counterproductive to US military objectives.

He said it would only embolden the United States' enemies.

"It would throw a lifeline to terrorists, who in recent months have suffered significant losses and casualties, been denied havens and suffered weakened popular support," he said.

The latest wave of attacks came after US and Iraqi officials had claimed successes in a Baghdad anti-insurgency offensive dubbed Operation Lightning launched in late May which saw more than 1000 suspects detained.

Iraq's most wanted man Abu Musab al-Zarqawi said in a purported Internet statement that an Al-Qaeda militant on Saudi Arabia's most-wanted list had been killed in fighting with US forces on the border.

Zarqawi said in a purported Internet statement that Abdullah al-Rashud, on Riyadh's list of most wanted militants, was killed during battles in al-Qaim, near the border with Syria where US forces have been fighting against insurgents. No date was given for his death.

The US military said a home in western Baghdad that served as a hideout for Zarqawi's Al-Qaeda linked group was destroyed and seven killed during a firefight with militants holed up inside.

Yesterday's early-morning violence came a day after some 80 countries pledged support for the new Iraq at a conference in Brussels and US forces announced the end of an operation against insurgents near the Syrian border.

In the first attack yesterday, a car blew up outside a Shiite mosque in a densely populated district of Karradah, and shortly afterwards a suicide car bomber blew himself up in front of a police patrol near a petrol station.

Minutes later a third car bomb blew up outside a hammam, a male bath complex, and a fourth exploded outside another mosque in Karradah but caused only damage.

The total toll from the attacks was 17 dead, including a number of policemen, and 69 wounded, according to an interior ministry official.

North of Baghdad, three Iraqis, including two soldiers, were killed when a suicide bomber driving a tractor blew himself up against a military convoy in the village of Albuzayla.

And a car bomb aimed at a US military convoy killed one Iraqi and wounded 10 others in the town of Tuz Khurmatu, security sources said.

A similar spate of bombings in another Shiite district of Baghdad on Wednesday killed 18 people.

Earlier Syria's Foreign Minister Faruq al-Shara promised Syria would cooperate more with Iraq on border security.

This follows US Secretary of State Condoleezza Rice's call to Damascus at the Iraq conference in Brussels to do more to secure its borders.

Beyond support for Iraq's political timetable, there were few new concrete gestures at the gathering, although Saudi Arabia signalled its willingness to forgive part of an Iraqi debt. - Sapa-AFP