Chilpancingo (Mexico), Nov 12 (IANS/EFE): Teachers protesting here in solidarity with 43 education students abducted -- and apparently slain -- in late September attacked the Guerrero state office of Mexico's ruling Institutional Revolutionary Party (PRI), sparking a clash with police.

Members of a teachers union arrived at the PRI headquarters in Chilpancingo, Guerrero's capital, shortly before 11 a.m. Tuesday and forced their way into the building.

The attackers, most of them hooded and armed with sticks, stones and Molotov cocktails, vandalised the offices and set fires before riot police intervened.

The union activists, camped out for weeks in Chilpancingo's main square, have mounted both peaceful and violent demonstrations over the case of the 43 missing students from Ayotzinapa Rural Normal School, a teacher-training institution near the town of Iguala, Guerrero.

News accounts said Tuesday's confrontation left several people hurt and ambulances were spotted at the scene, but authorities offered no information on the number of injured or the seriousness of their injuries.

The PRI's state chairman in Guerrero, Cuauthemoc Salgado, told Milenio Television that the attackers numbered between 400 and 500.

The roughly 60 percent people working inside the office at the time of the assault were able to leave the building, he said.

The 43 Ayotzinapa students were detained by police and handed over to the Guerreros Unidos drug cartel, which killed them and burned the bodies to eliminate all traces of the victims, Mexican authorities say, citing statements by suspects in the case.