Iraqi police say a suicide truck-bomb attack has killed at least 13 people and wounded more than 135 others in the northern city of Kirkuk.
Authorities say the attacker rammed his truck into a police compound near a school Monday and detonated his explosives. Many of the victims were children.
US troops were visiting the police compound at the time of the blast, and some were wounded.
In other violence, Iraqi officials say they found the bodies of 21 people, apparently Shi'ite workers abducted Sunday at a fake checkpoint north of the Iraqi capital, Baghdad.
In southern Iraq, small-arms fire killed one British soldier and wounded another.
Separately, the US military says an American soldier was killed Monday in a roadside bombing in volatile Anbar province, west of the capital.
The military said roadside bombs killed six American soldiers Sunday southwest of Baghdad.
Meanwhile, the US military says coalition forces killed six terrorists and detained 10 suspects Sunday and Monday during operations targeting couriers and car-bomb cells operated by the terror group al-Qaida in Iraq.
US Senator John McCain, who is seeking the Republican Party's presidential nomination, said during an unannounced visit to Iraq Sunday that the new US strategy of sending more forces to Iraq is working.