US Senators demand Rumsfeld's head

But the battlefield success hardly impressed two leading US senators, who on Sunday questioned the Pentagon's handling of the situation in Iraq and said they no longer had confidence in Defence Secretary Donald Rumsfeld.

Abu Zubair, also known as Mohammed Salah Sultan, was gunned down in the northern city of Mosul Friday, when he got caught in an ambush set up by Iraqi security forces, the officials said, confirming a report by Mosul police.

No other details of the operation were provided. But officials pointed out Abu Zubair was wearing a suicide belt filled with metal pellets when he was killed.

It was not immediately clear whether the suspect intended to become a suicide bomber himself or the belt was to be used by somebody else.

Abu Zubair was wanted for his alleged role in, among other things, organising a bombing attack on an Iraqi police station in Mosul last month, in which five policemen were killed, according to the defence officials.

They noted that Abu Zubair's death followed the capture of three bombmakers and six foreign fighters by US and Iraqi security forces last week.

"Abu Zubair's death, as well as recent captures of terrorists in northern Iraq, is making a difference in coalition and Iraqi security forces efforts to disrupt terrorists operating in this part of the country," Colonel Bill Buckner, a spokesman for the multinational force, told reporters.

He expressed confidence that bombings and other insurgent attacks "will not prevent Iraqi democracy."