Four US army soldiers have been killed in a roadside bombing northwest of Baghdad.

The US command said the soldiers were assigned on Tuesday to Task Force Baghdad which handles security in the capital and the surrounding area. No further details were released.

The deaths bring to at least 2149 the number of US service members to have died since the start of the Iraq war in March 2003, according to an Associated Press count.

White House

Meanwhile, the White House on Tuesday distanced itself from the figure of 30,000 Iraqis killed in the war, blaming "terrorists" for a significant number of the dead and saying the figure is not official.

US President George Bush on Monday had offered up that number during an impromptu question and answer session after a speech aimed at shoring up US public support for his strategy.

"He was citing what he has read in media reports," said spokesman Scott McClellan, who told reporters that while the Iraqi government may keep an official tally of Iraqis killed, Washington does not.

Asked what proportion resulted from US military action or the deadly violence that flooded the vacuum left by Saddam Hussein's ousting, McClellan replied: "I think that a significant number is attributable to the terrorists and the Saddam loyalists who are trying to prevent democracy from taking hold.

"The terrorists may be the smallest group [in the insurgency], but they are the most lethal group. And they indiscriminately target Iraqis - certainly Saddam loyalists have targeted Iraqis," he said.

"Our military goes out of the way to make sure that civilians are not targeted. And one of the things that the president has talked about in the past is how, because of the advances in technology, we were able to go in and remove a regime with minimal casualties to civilians," he said.

PHOTO CAPTION

Iraqi mourners carry the body of slain Sunni Arab candidate Mezher al-Dulaimi in Ramadi, Iraq Tuesday, Dec. 13, 2005. (AP)