At least 12 persons were killed after a bus collided head-on with a truck and turned over in Mendoza province in Argentina, officials said.The accident on Sunday, which took place along a highway outside San Rafael, a town in western Mendoza province, also left at least 20 others injured, Xinhua news agency reported."Most of the victims are dancers belonging to a dance group from Buenos Aires that was returning from Malargue (Mendoza), following a tourist visit," the daily La Nacion said on its website. An image of the crash site showed a bus turned over on its side, alongside what appears to be a curve in the highway.The injured were taken to an area hospital and the investigation to the accident was underway.