"Fierce fighting currently under way will demand further courage and further sacrifice," Bush told veterans groups in a White House ceremony driven indoors by threatening skies.

The media handwringing has given Bush "some level of frustration," a senior aide said Friday, adding that the president scorns talk of a "quagmire", which reminds many Americans of a long, bloody conflict like Vietnam.

"He thinks it's silly, not borne out by the facts," the aide told reporters on condition of anonymity before Bush himself highlighted the progress in the 10-day campaign to disarm and topple Iraqi leader Saddam Hussein.

"The regime that once terrorized all of Iraq now controls a small portion of that country. Coalition troops continue their steady advance and are drawing near to Baghdad. We're inflicting severe damage on enemy forces," he said.

Bush's appearance highlighted the president's power to communicate using the "bully pulpit" of the White House to make himself heard about the din of media judgements that US war planners underestimated Iraqi resolve and now face overstretched supply lines and fierce guerrilla fighting.

A senior battlefield commander, Lieutenant General William Wallace told The Washington Post in an interview published Friday that logistical problems and unexpected Iraqi tactics would likely draw out the conflict.

"The enemy we're fighting is different from the one we'd war-gamed against," he said, citing overextended supply lines and the willingness of Iraqi forces to launch suicide attacks as well as compel their own soldiers to fight.

Asked whether combat developments in the past week increased the likelihood of a much longer war than some planners had forecast, Wallace told the daily: "It's beginning to look that way."

The White House rejected that notion out of hand, insisted that the Bush administration had never forecast a quick and easy victory over Iraq, and upbraided doubters and those who say the US effort has bogged down.

"There's a difference between saying, 'what is your expectation about how long a war will last,' and some of the tone that has come out about 'why isn't it over yet,'" said Fleischer.

"The statements the White House has always made about this is that people should be prepared for the fact that it could go longer, be long, lengthy, dangerous," the spokesman said.

After a week of fighting, US forces are almost at Saddam Hussein's doorstep, officials here say, downplaying the fact that predictions of throngs of joyful Iraqis welcoming American soldiers have yet to materialize.

And they are still confident that troops will locate weapons of mass destruction in Iraq. Saddam denied possessing any such banned arms.

Fleischer dismissed notions that the decision to deploy 90,000 troops into Iraq and ready another 120,000 at US and European bases was a tacit acknowledgement of trouble, saying: "This is all part of the pre-written plan."

In mid-March, US Vice President Dick Cheney had given an optimistic timeframe for toppling Saddam, telling a television interviewer that the military campaign "will go relatively quickly, weeks rather than months."

"There's always the possibility of complications that you can't anticipate," he added.

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