The White House, on Thursday,gave a new vote of confidence to Rumsfeld as two more retired generals demanded that he resign.
Scott McClellan, the White House spokesman, said: "Yes, the president believes Secretary Rumsfeld is doing a very fine job during a challenging period in our nation's history."
The White House pointed to comments supportive of Rumsfeld from Marine-General Peter Pace, chairman of the Joint Chiefs of Staff, and said criticism was to be expected at a time of war in both Iraq and Afghanistan.
McClellan said: "We are a nation at war and we are a nation that is going through a military transformation. Those are issues that tend to generate debate and disagreement and we recognise that."
Scott McClellan: President believes
Rumsfeld is doing a very fine job
Rumsfeld has offered to resign at least twice, but each time Bush has turned him down.
Eric Ruff, a Pentagon spokesman, said Rumsfeld is ignoring the calls for him to quit and they have not been a distraction.
"Has he talked to the White House? The answer is no, he's not. And two, the question of resignation: was he considering it? No.
"I don't know how many generals there are - a couple thousand, at least. And they're going to have opinions."
Meanwhile, two more retired US generals have called for Rumsfeld's resignation, claiming that the chief architect of the Iraq operation ignored years of Pentagon planning for a US occupation and should be held accountable for the chaos there.
"I really believe that we need a new secretary of defense, because Secretary Rumsfeld carries way too much baggage with him"
Retd.Major Gen. Charles Swannack
Six retired generals, including the two who spoke out on Thursday, have now called for Rumsfeld to step down.
"I really believe that we need a new secretary of defense, because Secretary Rumsfeld carries way too much baggage with him," said retired Major. Gen. Charles Swannack, who led the Army's 82nd Airborne Division in Iraq.
"Specifically, I feel he has micromanaged the generals who are leading our forces," he told CNN.
Retired Major Gen. John Riggs told National Public Radio that Rumsfeld had helped create an atmosphere of "arrogance" among the Pentagon's top civilian leadership.
"They only need the military advice when it satisfies their agenda. I think that's a mistake, and that's why I think he should resign," Riggs said.
General Anthony Zinni, a retired marine, added to the pressure for Rumsfeld's scalp by telling CNN that Rumsfeld should be held accountable for a series of blunders, starting with "throwing away 10 years worth of planning, plans that had taken into account what we would face in an occupation of Iraq."
2360 US soldiers died in Iraq
under the Bush administration
His views were supported by other commanders who served under Rumsfeld.
The demands for Rumsfeld's departure came as opinion polls show eroding public support for the 3-year-old Iraq war in which about 2,360 US troops have died and Bush is struggling to bolster Americans' confidence in the war effort.