US President George W Bush has called on Iraqis to "defy terrorists" and vote in Sunday's election as violent attacks by insurgents continued across Iraq.
Bush said Iraq's insurgents were "afraid of a free society"
Mr Bush was speaking on the deadliest day for American troops since the US-led March 2003 invasion.
Thirty marines and a sailor died in a helicopter crash in western Iraq, although officials said there was no indication of hostile action.
In separate incidents, six US troops and at least 22 Iraqis were killed.
"I urge all people to vote. I urge people to defy these terrorists," Mr Bush told reporters in Washington.
"I am impressed by the bravery of the Iraqi citizens. I anticipate a grand moment in Iraqi history," he said.
An inquiry has been launched into the chopper's crash
The president refused to say what sort of turnout he was hoping for, but stressed that "the fact that they're voting in itself" was a success.
Asked about America's intentions after the 30 January election, Mr Bush said the mission would be completed as soon as possible.
"The enemy would like nothing more that the United States to precipitously pull out and withdraw before the Iraqis are prepared to defend themselves," he said.
Mr Bush's comments came as US Defence Secretary Donald Rumsfeld warned that rebels could step up their attacks after the poll.
"One has to expect the level of violence will either stay where it is or go up or down modestly during this period as they attempt to prevent from happening that which is going to happen," Rumsfeld told reporters.
In other developments on Wednesday:
- At least 15 people are killed in a car bomb blast outside Kurdistan Democratic Party in northern Iraq - making it the day's deadliest attack
- At least five people are killed by three car bombs in the town of Riyadh, near the northern city of Kirkuk
- A US soldier is killed when an army patrol comes under attack in northern Iraq.
- In Baghdad, one US soldier is killed and two others are injured in a roadside bombing.
- Undersecretary of Defence Douglas Feith, a leading Pentagon hawk and an architect of the US policy on Iraq, will stand down in the coming months, US officials say
The president was speaking just hours after the helicopter crash near the western town of Rutbah.
US HELICOPTER LOSSES IN IRAQ
15 Nov 03: Two Black Hawks collide while trying to avoid ground fire in Mosul, killing 17
2 Nov 03: Chinook shot down near Falluja, killing 16
8 Jan 04: Black Hawk shot down near Falluja, killing nine
9 Nov 03: Black Hawk comes down near Tikrit, killing six
The helicopter, a CH-53E Super Stallion, was flying over the desert when it went down at about 0120 local time (2220 GMT Tuesday), the US military said.
Gen John Abizaid, commander of US troops in Iraq, said the helicopter was on "a routine mission in support of the elections".
Reacting to the deaths, Mr Bush said: "Anytime we lose lives, it is a sad moment."
US troop numbers were recently boosted to 150,000, to improve security during the Iraqi election.