A clash between Mexican police and teachers who blocked Acapulco's airport left one demonstrator dead, while seven officers were injured when protestors struck them with a bus, officials said Wednesday.

Some 5,000 protestors demanding better pay and justice in the case of 43 missing trainee teachers had been preventing access to the Pacific resort city's airport for six hours on Tuesday when riot police intervened.

"Unfortunately I have confirmation of one death. I couldn't determine the cause, but it was a person with head trauma who was being transported in an ambulance," Raul Miliani, an official for civil protection in Guerrero state, told Radio Formula.

Manuel Rosas, a spokesman for the radical CETEG teachers union, said the man was 65-year-old retired teacher Claudio Castillo and that he had been hit by police officers.

At least 112 people were detained, Rosas said.

The interior ministry said police had tried to talk the protestors into reopening access to the airport. It did not say how many people were arrested.

"The reaction of the protestors was to attack the police contingent with a bus that they had used for their transportation," the ministry said in a statement late Tuesday.

The demonstrators also threw rocks and other objects at the police, the statement said.

Seven officers were injured when they were struck by the bus and five demonstrators were hurt in the scuffle, the ministry said.

The CETEG union has held several protests demanding better conditions for teachers in impoverished states. They have also led demonstrations to demand the return of the disappeared 43 college students.

Authorities believe the young men were abducted by corrupt police in the city of Iguala and delivered to a drug gang, which slaughtered the group.