In Baghdad, a delegation of US senators told Ibrahim al-Jaafari, the Iraqi prime minister, that Americans were growing impatient over the delay in forming a unity government in Iraq.
At a White House news conference, the president acknowledged the public's growing unease with the war in Iraq and election-year nerves among fellow Republicans but nonetheless vowed to keep US soldiers in Iraq.
"If I didn't believe we could succeed, I wouldn't be there. I wouldn't put those kids there," Bush said.
The president stood by Donald Rumsfeld, the embattled US defense secretary.
"I don't believe he should resign. He's done a fine job. Every war plan looks good on paper until you meet the enemy," Bush said.
The president again said he disagreed with those who felt that Iraq was in a civil war.
"We all recognised that there is violence, that there is sectarian violence. But the way I look at the situation is the Iraqis looked and decided not to go into civil war."
Nearly four out of five Americans, including 70% of Republicans, think civil war will break out in Iraq, according to a recent AP-Ipsos poll.
In Baghdad, Republican Senator John Warner, head of the powerful Senate Armed Services Committee, said he and five fellow senators delivered a clear message from the US public.
"The American people are of good heart ... but do not try in any way to deceive them or let this progress indicate to the world a less than sincere and prompt effort to bring about a new government," Warner said.
"(Otherwise) Americans will speak up and speak up very loudly," he said, adding that he had made this point three times in "forceful and pointed" comments to Jaafari.
Warner said he also told Jaafari that in the event of Iraq descending into civil war it would be the responsibility of Iraq's police and army primarily to quell the violence, not US-led forces.