The U.S. military says four Iraqi civilians were killed and 19 people, including two American soldiers, were wounded when a car bomb exploded near a U.S. military convoy in the northern town of Baiji Tuesday.
In a separate attack -- also in Baiji -- insurgents fired a rocket-propelled grenade at a U.S. tank, wounding one soldier.
Insurgents have recently stepped up their violent campaign - particularly in Iraq's Sunni dominated regions - to derail the country's January 30 election.
Major Sunni Muslim and Kurdish parties have called for a six-month delay in the vote. But parties representing Iraq's Shi'ite majority say the election should go ahead as planned.
U.S. Secretary of State Colin Powell says the election is a way for Iraqis to take a stand against the insurgents.
Some information for this report provided by AP, AFP and Reuters.