At least three suicide bombings struck a police headquarters in the restive central Iraqi city of Baquba on Sunday, killing three policemen, security and medical officials said.
The blasts went off at about 8:00 pm (1700 GMT) and followed by clashes in the surrounding area of Mafreq, with officials warning the casualty toll could rise as medical teams did not have full access to the sites.
An initial car bomb was detonated by a suicide bomber outside the headquarters of a police battalion in Mafreq, and in the ensuing chaos, another suicide bomber blew himself up.
A third bomber subsequently managed to enter the battalion compound and blew himself up at the entrance to the main building.
Officials said security forces were chasing a fourth bomber as well.
Clashes also broke out in three other neighbourhoods of Baquba, which lies 60 kilometres (35 miles) north of the capital in one of the country's least stable provinces.
Elsewhere in Iraq on Sunday, six people were killed, the latest in a months-long surge in violence that the authorities have largely failed to stem despite wide-ranging operations and tightened security measures.