Mexican activist Atilano Roman Tirado shot dead by gunmen during live radio broadcast

It comes as mass protests hit the country over the disappearance of 43 students following a confrontation with police

A student of the Ayotzinapa Teacher Training College "Raul Isidro Burgos" throws a stone during a protest (Reuters)

A Mexican activist was shot dead after two gunmen forced their way into a radio studio during a live broadcast and opened fire, prosecutors have said.

Listeners could hear the gunshot which killed Atilano Roman Tirado, who had a weekly radio programme at the Fiesta Mexicana station in Mazatlan, in the state of Sinaloa.

Station director Sergio Ontiveros said yesterday that the transmission was cut off as a colleague dove to the floor and kicked out the master cable during the incident.

He said: "On air you could hear when the shot is fired, and then one of the co-workers is heard saying, 'Oh no, he killed him, he killed him.'"

He added: "That is when the transmission cut off... The station operator dove to the floor and kicked out the master" cable.

Meanwhile, hundreds of protesters smashed windows and set fires inside a Mexico state capital building today over the disappearance of 43 students following a confrontation with police more than two weeks ago.

The protesters called for the students to be returned alive. The students, from a rural teachers' college in Guerrero state, have been missing since September 26. Fears have grown that ten newly discovered mass graves could contain their bodies.

Jose Villanueva Manzanarez, spokesman for Guerrero's government, said members of a teachers' union initially tried to get into the state congress in Chilpancingo but were repelled by anti-riot police. They then headed to the state government palace.

The teachers, along with hundreds of students from the Ayotzinapa teachers' college, blockaded the capital building, attacking it with battle bars, rocks and Molotov cocktails, he said.

The violence came more than two weeks after police in Iguala, also in Guerrero state, opened fire on the teacher's college students, killing at least six.

Witnesses have said that dozens of students were taken away by police and have not been seen since. Twenty-six local police officers have been detained, and officials are attempting to determine if any of the students are in the mass graves nearby.

Anti-riot police are on guard as students try to get into Government palace, in Chilpancingo (EPA)

In Sinaloa, Mr Roman Tirado was one of the leaders of roughly 800 families demanding compensation for being displaced by the Picachos dam.

The movement has, in previous years, staged blockades and protest marches, which had resulted in some arrests.

Mr Ontiveros said the activist focused on the land dispute, along with other news, in his programme 'Asi es mi Tierra', which roughly translates as 'That's how my land is.'

The station director said: "He was militant in his commentaries, he was critical, very critical.

"His situation almost demanded that of him."

The station was off air for about half an hour following the incident. It was operated remotely over the weekend before resuming normal operations on Monday.

Mr Ontiveros described how the gunmen "violently forced their way in" to the studio.

Firefighters attempt to extinguish a fire at the Municipal Palace in Chilpancingo (AFP)

"They asked for Atilano. The receptionist said he was there and said if they waited, she would tell him they wanted to see him," Ontiveros said. "But they pushed open the door and forced their way in to the studios."

An employee was hit with the butt of a pistol before Mr Roman Tirado was shot in the head and in the chest with a 9mm pistol. He died later in hospital.

Sinaloa Gov. Mario Lopez Valdez said the killing would not go unpunished. Officials had reported no arrests on Monday, the Associated Press reported.

State prosecutor Marco Antonio Higuera said the station offices did not have security cameras that might have recorded the killing.

Additional reporting by Associated Press and Press Association