Insurgents shot dead 11 Iraqi police and police trainees in two separate, daylight attacks on Tuesday, the latest deadly strikes against Iraqis working with the US-led occupation.
Reuters Television footage showed a yellow minibus riddled with bullet holes, the seats splattered with blood.
"They were killed at around 7.30 this morning (0430 GMT)," Mussayab Police Chief Major Kadhim Ajmi told Reuters.
"They were shot by unknown attackers driving a red Opel."
Local officials said the minibus was attacked shortly after leaving the town of Mussayab on its way to Hilla, about 100km south of Baghdad. Staff at Mussayab General Hospital said three other passengers were wounded.
Police have often been attacked by insurgents who accuse them of co-operating too closely with the US-led occupiers. Two policemen were killed in another drive-by shooting on Tuesday, near the northern city of Kirkuk.