Baquba - Insurgents killed 15 unarmed Iraqi police trainees and wounded 24 more in an ambush on their buses on Sunday, Diyala province police chief Major-General Ghassan al-Bawi told AFP.

"They were being brought home to Baghdad from the training centre for a new emergency response brigade when insurgents set up a roadblock to stop them and opened fire," he said.

The police are a target of choice for the insurgent gangs fighting Iraq's murderous civil conflict and the scene of the attack, a road north of Baghdad, is in an area wracked by sectarian conflict.

An interior ministry official said the buses were halted by a roadside bomb, but that most of the deaths were caused by ambushers firing on the passengers.

Some of the officers thought to have been onboard were missing and many of the bodies left behind had been booby-trapped, he added.

"There is a plan in our province to train 2 500 policemen to form a new rapid intervention brigade.

"We have given a former police dog training school outside Baquba," Bawi told AFP.

"Tonight the terrorists attacked them outside the school."