Clashes between police and members of a radical teachers' union have left six dead and over 100 people people injured in the southern Mexican state of Oaxaca.
Protesters have accused the police of "a massacre." The police have blamed "violent groups" within the protest movement.
The violence erupted on Sunday when riot police moved in to break up a road blockade near the town of Nochixtlan, about 50 miles from the state capital, also known as Oaxaca. Footage of the moment shows molotov cocktails flying as crowds run from the scene and gunfire can be heard.
The union released a statement on Sunday afternoon accusing the police of shooting at them "with direction and viciousness," and claimed "the people" had "resisted with clean hands."
An initial government statement countered that the federal police were not carrying weapons and stated "it is known" the shooters were infiltrators in the protest movement. Film shot by reporters at the scene, however, show riot police firing on protesters, though it is not clear whether they are federal of state police.
A second government statement released late on Sunday night was more vaguely worded. It said that "different violent groups" related to the blockades were "mainly to blame" for the violence.
As well as confirming the death toll at six, the later statement said 53 civilians were injured, as well as 55 federal police officers, eight of them with bullet wounds.
A little earlier, Oaxaca governor Gabino Cue had confirmed that none of the dead were police officers and told reporters only two had ties to the National Coordinator of Education Workers, or CNTE — the radical teachers' group at the heart of the protests against sweeping education reforms.
The government has relentlessly promoted the reforms, which include mandatory teacher evaluations, as the answer to Mexico's dismal state schools. The teachers claim they are being unfairly blamed for the failures of a system that is broken at its core. They also charge that the reforms are laying the ground for future privatization.
Periodically violent protests have been going on for years, but the tension has increased dramatically in recent weeks as the government steps up its implementation of the reforms, including the imposition of sanctions against striking teachers.
This weekend's clashes also come a week after the Oaxaca teachers promised revolt in response to the arrest of local leader Rubén Nuñez on money laundering charges. Ten years ago radical Oaxaca teachers led a broad alliance of social groups in an uprising against then governor Ulíses Ruíz that paralyzed Oaxaca city for almost six months.
Related: Mexico's dissident teachers union CNTE proves tough to tame
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