A police helicopter flies overhead as the Guerrero state capital building burns after it was set on fire by protesting college students in Chilpancingo, Mexico. (Photo: AP)

Chilpancingo, Mexico: Protesters torched part of the government headquarters of Mexico's southern state of Guerrero on Monday amid demonstrations demanding the return of 43 students missing since an attack by gang-linked police.

Hundreds of students and teachers ransacked the government complex in the state capital Chilpancingo, allowing workers to leave before breaking windows and setting a building on fire. The protesters called for Governor Angel Aguirre to resign as they left the area. State police later came in while firefighters battled the blaze.

The attack on Aguirre's offices came after clashes between riot police and protesters armed with rocks and sticks at the gates of the state congress. The police was able to push back some 500 protesters from the state legislature. Five teachers and two officers were injured, an AFP correspondent said.

Students from a teacher training college outside Chilpancingo have been fuming over the fate of 43 comrades who vanished after their buses were shot at by municipal police in the city of Iguala on September 26.

Authorities are investigating whether the students were buried in mass graves found outside Iguala, some 200 kilometers (125 miles) south of Mexico City. Prosecutors have detained 26 Iguala police officers in the case, accusing them of colluding with the Guerreros Unidos gang in a night of violence that also left six people dead and 25 wounded. Four gang members were also arrested along with four other unidentified people.