Mexico missing students: Protesters clash with police
Mexican police have clashed with protesters organising a concert in the city of Chilpancingo in support of a group of 43 students who went missing more than two months ago.
Police said several officers had been injured, including some who were knocked down by a vehicle.
The two groups accused each other of starting Sunday's violence.
The case of the missing students, one of whom has been found dead, has triggered protests across Mexico.
Police said eight officers were injured, five of whom were run over by a car.
They said three others had been beaten by the protesters.
The protesters said 13 people, including relatives of the missing students, were injured.
The violence erupted after the protesters had erected barricades in a street in Chilpancingo ahead of a planned concert in support of the missing students.
The concert was cancelled after the clashes, during which a number of cars were set alight.
Tensions have been running high between supporters of the missing students and the police for weeks.
The group of 43 students from a teacher training college in Ayotzinapa disappeared on 26 September after clashing with municipal police in the town of Iguala.
Missing Mexican students
26 Sept Ayotzinapa: Students depart college
26 Sept Iguala: Students clash with police following protests
27 Sept Cocula: Forty-three students taken to the police station before being allegedly handed over to local drugs gang
Early Nov Puente Rio San Juan: Remains discovered - in a stream and at a rubbish dump where the gang had allegedly burned the bodies
Municipal officers have told investigators they seized the students and handed them over to a local drugs gang.
Members of the gang said they killed the 43 and burned their bodies at a rubbish dump after they were told the students belonged to a rival gang.
Tests carried out on a bone found in a river near the dump suggest it belonged to one of the 43 missing students, Alexander Mora.
The relatives of the other 42 missing students say they will not give up hope of finding them alive until forensic evidence proves they are dead.
The slow pace of the initial investigation into their disappearance and the collusion it has highlighted between local authorities and drug gangs has led to mass protests across Mexico.