Protesters in the Mexican state of Guerrero ransacked government headquarters on Monday, escalating demonstrations over the disappearance of dozens of students last month.
Hundreds of people broke windows and set fire to the state capital building in Chilpancingo after workers had left for the day. It was the latest protest over 43 teachers' college students who remain missing after clashes with police in the town of Iguala.
Authorities have arrested at least 22 police officers and several gang members in a case that links security forces to organized crime.
There has been no sign of the teacher trainees since their disappearance on September 26. DNA testing is underway to determine whether charred bodies found in mass graves in Iguala last week are the students.