Iraq's interim President Ghazi Yawer has reaffirmed his support for the planned 30 January elections, despite continuing attacks by insurgents.
Yawer said he hoped US troops would leave Iraq within a year
Speaking ahead of talks with the US president, Mr Yawer said any delay would prolong Iraqis' agony and increase resentment inside the country.
George W Bush said earlier that the poll should be held as planned.
On Sunday, insurgents killed at least 21 Iraqis in a series of attacks across the whole country.
Sunday's attacks on people working with or for coalition forces took the number of Iraqis killed since a resurgence of violence on Friday to at least 68.
"We do not think that postponing elections... will solve the problem," Mr Yawer told NBC's Meet the Press programme in Washington.
Insurgents are targeting Iraqis more and more
"Actually, it will prolong the agony for Iraqis and will have more resentment in the Iraqi society," he said.
Mr Yawer's comments echoed the words of Iraqi interim Foreign Minister Hoshyar Zebari who said earlier: "The elections are difficult but they are do-able".
Mr Yawer also expressed hopes that US troops could be withdrawn within a year if Iraq's security forces would be able to take over.
"It will take months... Six months or eight months or a year. But I don't think it will take years. Definitely not," Mr Yawer said.
On Sunday, 17 civilians working for the American military died and 13 more were hurt when gunmen opened fire on a bus taking them to a base in Tikrit.
Capt Bill Coppernoll, of the US 1st Infantry Division, said gunmen opened fire as Iraqis arrived for work at a base in Tikrit, Saddam Hussein's hometown, at about 0830 (0530 GMT).
"Two vehicles opened fire on a civilian bus that had stopped to let the workers off, who were employed by coalition forces," he said.
Gen Abizaid said the Iraqi army was developing too slowly
Capt Coppernoll said there was another attack about an hour later when a suicide car bomber drove into an Iraqi National Guard checkpoint in Beiji, about 120km (75 miles) north of Tikrit.
Elsewhere on Sunday, four members of the Iraq security forces were killed in the towns of Beiji and Samarra.
The Iraqi Red Crescent said it has withdrawn from Falluja amid concerns about security in the city that was the scene of intense fighting last month during a US-led assault.
US troops and insurgents are still clashing in several parts of the city, and a Red Crescent spokeswoman it was difficult for staff to remain during the continuing military operation.
US forces denied reports that they had told Red Crescent to pull out, saying the agency - the only relief agency working in Falluja - left of its own accord.
Money and motivation
The top US commander in Iraq, Gen John Abizaid, said earlier that local forces are not up to the task of protecting the election by themselves and still need US help.
Gen Abizaid, the head of US Central Command, called on Iraq's neighbours - in particular Syria and Iran - to do more to curb the flow of foreign fighters into Iraq.
"It's very important for everybody to realise that the stability of Iraq is as dependent on its neighbours as it is on the people inside Iraq," he said.
He also expressed disappointment that the Iraqi army was still developing too slowly to cope with the security situation.
The Pentagon announced that the US will boost its troop levels to 150,000 by mid-January - an increase of 12,000 personnel.