A bomb exploded near an Iraqi army patrol south of Baghdad on Wednesday, killing six soldiers, an officer and a hospital employee said.

The blast struck the patrol in the Jurf al-Sakhr area, where mortar rounds wounded 12 police on Tuesday.

It followed an attack by militants that killed 15 soldiers guarding an oil pipeline in northern Iraq.

Security force personnel have been frequently targeted by militants, as the government grapples with the worst unrest since 2008.