A suicide bomber has blown himself up at a military recruiting center in Baghdad, killing at least 12 people, the Associated Press reports.

A police official said the attacker struck on Thursday, Jan 9 morning, and that at least 25 people have been wounded in the blast.

A hospital official confirmed the casualty numbers. Both officials spoke on condition of anonymity because they were not authorized to talk to media, according to the AP.

There was no immediate claim of responsibility, but suicide attacks are the hallmark of al Qaeda's Iraq branch.

Its fighters last week overran parts of two key cities west of Baghdad — Fallujah and Ramadi — and have been clashing with Iraqi forces trying to drive them out.

The attack on the recruiting center could be a retaliation for the military's offensive.