Two separate suicide bombings killed 21 people in Iraq on Wednesday as part of a campaign to derail the Jan. 30 general elections.

In the town of Hilla, south of Baghdad, a suicide bomber blew up a car loaded with explosives outside a police academy during a graduation ceremony, killing 15 people, said the police.

Hours later in Baquba, another suicide bomber killed six Iraqi policemen at a checkpoint manned by police and National Guards, police and hospital sources said.

The attacks were the latest by insurgents who have killed more than 90 people, mostly policemen, so far this week in a campaign aimed at derailing this month's elections and targeting the US-backed interim government and its security services.

Despite the mounting attacks and rising casualties, Iraq's interim leader vowed again to proceed with the vote as planned.

"The government is committed to running the elections on schedule," Iraqi Prime Minister Ayad Allawi told a news conference. "We will not allow violence and terrorists to stop the political process."