Striking teachers in Mexico's Guerrero state have attacked the offices of four major political parties and a building of the state's education department.

They destroyed computers and furniture and set fire to two buildings in anger over legislators rejecting their strike demands.

Teachers in the state capital of Chilpancingo marched Wednesday to each of the five buildings, breaking windows and vandalizing offices. They set fire to the state headquarters of the ruling Institutional Revolutionary Party and another building. No injuries have been reported.

The 20,000-member group went on strike shortly after President Enrique Pena Nieto signed into a law a sweeping education reform two months ago. Its members have since staged increasingly disruptive protests.