Updated

U.S. forces and diplomats are taking a sideline role as Iraqis head to the polls Saturday for the first time since the drop-off in violence last year.

Despite the killings of three candidates Thursday, officials have high hopes for a large turnout -- especially in Sunni areas where many stayed away from the last elections in 2005 due to violence, intimidation and voter apathy.

"This Iraqi election is a milestone in Iraq's democratic development," State Department spokesman Robert Wood said Friday. "We think this is a real important step on the way to Iraq becoming a very mature democracy. ... When you look at the violence that took place in previous elections and compare it to what we've seen up until now, I think it's a very positive sign."

He said U.S. officials are looking for a "free, fair, transparent election, free of violence."

Iraqis are responsible for organizing, managing and providing security for the elections, in which more than 14,400 candidates are competing for 440 seats in 14 of 18 provinces. Iraqi forces are already sealing borders and imposing overnight curfews in some of the country's biggest cities.

The U.S. military plans to send heavy troop deployments into the streets during voting, but coalition forces are in a largely auxiliary role. The Multi-National Force in Iraq is providing assistance as needed, according to the State Department, and has worked on planning to prevent acts of violence and intimidation.

The United Nations and European Union are coordinating international observers, and diplomats from the U.S. Embassy and other countries will be present as monitors.

Brig Gen. David Perkins, with the Multi-National Force in Iraq, told FOX News that the average number of daily attacks has dropped dramatically since the elections in January 2005. He said Iraq averaged 92 attacks per day then, compared with five on Thursday.

"You see this huge improvement in security already under the leadership of Iraqis, so obviously the trend's in the right direction," he said. But he added that the recent slayings of candidates have caused "major concern."

Woods said "there's no question" violence is still a problem, but that security provides a better climate for a "free and fair" election.

The Associated Press contributed to this report.