Mexico teachers clash with police in Zocalo Square
Police in Mexico City have clashed with protesters during an operation to clear a square occupied by striking teachers.
Riot police used tear gas and water cannons to remove the protesters from the city's main square, the Zocalo.
Striking teachers had been camped out there for weeks. Some responded with petrol bombs as police moved in after a government deadline passed.
The teachers have been demanding changes to education reforms approved by President Enrique Pena Nieto.
The authorities said they wanted to clear the Zocalo for the Independence Day celebrations at the weekend.
Most of the protesters left peacefully by Friday's deadline. But some stayed on, and police backed by armoured vehicles and helicopters clashed with missile-throwing protesters on the square and in nearby streets.
Officers tore down the teachers' temporary shelters and put out small fires started by the demonstrators and made a number of arrests.
The BBC's Will Grant in Mexico City says government's aim of clearing the square has been achieved - but the sight of riot police and armoured vehicles in the country's most emblematic plaza is not the image of unity it wanted to portray hours before Mr Pena Nieto's first Independence Day as president begins.
Our correspondent says that some of the demonstrators were thought to be radical anti-government activists who were not necessarily associated with the teachers union.
The educations reforms introduced by the government include performance-related tests for teachers.
Critics accuse Mexico's teachers' unions of being corrupt and having too much control over job allocation.
Last week, thousands of its members protested outside the Senate in an attempt to disrupt the passing of the bill, which had already been approved by the Chamber of Deputies.
The National Education Workers' Co-ordinator (CNTE) has been most vocal in protesting against the reforms, which it says will lead to mass lay-offs.
CNTE union members argue that the compulsory test are a way for the government to sack teachers en masse.
They also say that the tests will not take into account the difficult conditions teachers in the poorest regions of Mexico have to work under.
Juan Garcia, a teacher from the southern state of Oaxaca, said he hoped the protests would garner support from Mexicans across the country, who he invited "to join the struggle for a continuation of a free education system".
The government has argued that union control over teaching jobs has contributed to corruption, which has seen poorly trained teachers promoted over more qualified colleagues.