"I'd like to express our regrets to the families of the Iraqis killed yesterday day at the checkpoint near Al Najaf. The loss of any innocent life is truly tragic," said General Richard Myers, chairman of the US joint chiefs of staff.

But he also blamed "the climate established by the Iraqi regime" as contributing to the shooting at a checkpoint at Najaf, 150 kilometersmiles) south of Baghdad, on Monday afternoon.

The victims were in a vehicle that failed to stop despite hand signals and repeated warning shots fired by US troops, who then fired at the passenger compartment as a last resort, US spokesman Navy Lieutenant Commander Charles Owens said.

US President George W. Bush also offered his "regrets" at the deaths of Iraqi civilians, but blamed the casualties on Saddam as the White House sought to deflect mounting criticism over its war plan.

Defense Secretary Donald Rumsfeld has come under increasing scrutiny from US dailies, with The New York Times reporting Tuesday that top military officers accuse him of interfering with the planning for war in order to limit the number of troops deployed to Iraq.

Rumsfeld has fervently denied the allegations.

With US forces seeking a second wind as they push towards Baghdad, the daily quoted one colonel anonymously as saying that Rumsfeld "wanted to fight this war on the cheap" and adding "he got what he wanted."

A White House official told reporters on condition of anonymity that "the president has tremendous faith in secretary Rumsfeld and his generals, secretary Rumsfeld's leadership, secretary Rumsfeld's decisions. And that's borne out by what the president views as a successful military campaign."

"The Pentagon is a big building and there's a thousand colonels," making it easy to find at least a handful willing to criticize civilian leaders in the newspapers, the aide said.

"We're a free country and everybody is allow to criticize. People have that right," White House spokesman Ari Fleischer said later. "The president has faith in the plan, accepts the plan, the plan is working."

Bush will deliver a fresh progress report on the war Thursday during a day-long trip to Camp Lejeune, North Carolina, home to many of the 47,000 Marines currently serving in Iraq, said Fleischer.

Rumsfeld denied rumors of a cease-fire negotiation or a third party peace plan for Iraq, telling reporters: "There will be no outcome to this war that leaves Saddam Hussein and his regime in power. Let there be no doubt."

US officials again cast doubt on whether Saddam was still alive, with Fleischer saying that his failure to deliver a threatening televised speech personally "raises interesting questions."

Secretary of State Colin Powell headed across the Atlantic in a bid to mend relations battered by the US-led war.

Powell arrived in Turkey late Tuesday. He was set travel to Brussels to meet with European Union and NATO foreign ministers on Thursday, and also to visit Belgrade.

Turkey shocked US war planners when its parliament voted against allowing 62,000 US troops on its soil to open a northern front in Iraq.

Washington's strategy in Iraq has deeply divided its European partners and put strains on transatlantic relations.

WAR.WIRE