Iraqi police say a roadside bomb blast south of Baghdad has killed seven police officers.

The policemen were in a convoy traveling on a road east of the city of Diwaniyah.

The region south of Baghdad is known for frequent clashes between rival Shi'ite groups and violence against U.S.-led forces.

North of Baghdad, authorities say a suicide truck bomber hit a checkpoint operated by Kurdish peshmerga militiamen at Jalawla in Diyala province, killing one and wounding 10.

Separately, the U.S. military says coalition forces detained 15 suspects in operations targeting al-Qaida in Iraq terrorists in central and northern parts of the country early Wednesday.