Students and teachers smashed windows and set fire to the Guerrero state capitol building on Monday, demanding answers over mass graves linked to police.

The protesters are angry at authorities’ failure to deal with the disappearance of 43 young people who are believed to have been abducted by local police linked to a drug cartel.

They called for the students from a rural teachers’ college, who have been missing since September 26, to be returned alive.

But fears have grown that 10 newly discovered mass graves could contain their bodies.

Guerrero state government spokesman Jose Villanueva Manzanarez said that members of a teachers’ union had initially tried to get into the state congress in Chilpancingo.

They were repelled by anti-riot police before heading to the state government palace.

With the support of hundreds of student teachers from the Ayotzinapa college, the protesters blockaded the capitol building, attacking it with iron bars, rocks and Molotov cocktails, he said.

Guerrero state police killed at least six teacher training college students two weeks ago in the town of Iguala.

Dozens of students were subsequently taken away by police and have not been seen since.

Twenty-six local police officers have been detained and officials are attempting to determine whether any of the students are in the nearby mass graves.

The confrontation in Iguala shed light on a widespread problem, with local police often linked to organised crime.

The Iguala police who attacked the students were working with local cartel Guerreros Unidos, according to those arrested.