After the demonstrators blocked the roadway for hours Friday, causing a huge traffic backup, hundreds of federal police cleared protesting teachers from the main highway between Mexico City and Acapulco.

The teachers were protesting an educational reform that will submit them to evaluation and loosen union control over hiring and firing. Teachers had blocked the four-lane highway at least twice for before, starting in March.

A photographer on the scene said helmeted police with shields pushed into the crowd of teachers, who fought back with pointed staves. Police responded with tear gas.

Deputy Interior Secretary Manuel Mondragon told local media that four police officers had been injured, none seriously, and said several people had been arrested.

In a statement, the federal police said they had not used any firearms during the raid. They said protesters had used sticks, stones and gasoline bombs.

The government of Guerrero state, where Acapulco is located, said in a statement that traffic was flowing freely on the highway by late Friday.

Gov. Angel Aguirre had previously held talks with the protesters, and asked them to stop blocking highways because of the damage it was doing to the tourist resort.

During previous blockades, some Acapulco-bound tourists had cancelled hotel rooms and vacation plans because of the highway blockades. Hotel owners and business groups had filed legal complaints against the teachers because of the lost income.

Teachers' union representative Manuel Rodríguez Galvez said the teachers had blocked the highway to demand a meeting with Aguirre, a demand that wasn't met. The teachers' union had submitted a proposal to change the national education reform to reflect what the teachers' claim is the complex rural and indigenous social fabric of Guerrero state, but the state congress rejected that proposal.

Based on reporting by The Associated Press.

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