Mexican authorities and protesters traded accusations of responsibility Monday for weekend clashes in which at least six people died and more than 100 were wounded in the restive southern state of Oaxaca.
Federal Police Chief Enrique Galindo, speaking on local Radio Fórmula, said few teachers were involved in the violence and attributed it to other, unspecified "radical groups."
However the radical teachers' union involved in the protests denied that and alleged that police infiltrators were to blame.
The clashes are the latest flashpoint in an ongoing battle for control of public education in Oaxaca, where the union is vehemently resisting government attempts to implement national education reforms passed under President Enrique Peña Nieto.
Galindo said things initially went smoothly Sunday when officers moved to reopen the highway around 7 a.m. after it had been blocked by protesters. Traffic flow resumed for about two hours following dialogue between unarmed police and demonstrators from the National Coordinator of Education Workers, or CNTE.
But later the crowd swelled to about 2,000 protesters, some of them armed with gasoline bombs and powerful fireworks, Galindo added. When police confirmed gunshots, he ordered armed police to move in.
"It was a radical change of scene," Galindo said. "It was practically an ambush."
He reported that seven officers suffered bullet wounds, others had serious burns on their hands and feet and some lost fingers.
Six people were killed and more than 100 were wounded before police pulled back, he said, adding that "staying in Nochixtlán would have brought more serious consequences."
In a news conference late Sunday, Oaxaca state Gov. Gabino Cué said all the dead were civilians and two had ties to the CNTE union.
On Monday the CNTE said eight had been killed and 20 more were missing. It said the dead comprised teachers and members of other social groups that support them.
But the union denied the presence of "radical groups" and said police had infiltrated their movement. It demanded Cue resign and blamed him and national Education Secretary Aurelio Nuño for the upheaval in the state.
"This movement is not going to stop," union member Juan García said at a news conference. "They had their opportunity to resolve it with dialogue and discussion."
Galindo said he did not know if police had fired any of the fatal gunshots. Video filmed by The Associated Press showed at least one officer firing a gun several times, though it was unclear if he was a federal or state agent.
About 100 to 150 protesters maintained the roadblock on Monday in Nochixtlán, where about a half-dozen burned vehicles littered the area and there were no police in sight. Protesters were allowing people to pass on the highway but continued to block commercial traffic.
Galindo said there were a number of blockades around the state and officials would try to resume talks with the teachers, who planned a march in the capital, also called Oaxaca.
Mexico's National Human Rights Commission reported that journalist Elpidio Ramos Zárate of the newspaper El Sur del Istmo in Juchitan de Zaragoza, Oaxaca state, was killed Sunday, but it was not immediately clear if it was related to the protests.
Teacher protests have been going on for years in Oaxaca; a decade ago, the union launched a six-month takeover of central Oaxaca city that only ended after police stormed the barricades.
Mexico's education reform aims to wrest control over struggling schools from unions that have often had sole power over hiring, firing, promotions and budgets. The CNTE strenuously opposes a new system of teacher evaluations and rules allowing for educators to be dismissed if they miss too many schooldays.
Federal prosecutors accuse union leaders of setting up an illegal financial network to fund protests and line their own pockets. They allege the scheme operated in 2013-2015, when the union effectively controlled the payroll of Oaxaca's teachers.
Following the recent arrest of some if its top leaders, the union called for a revolt. In the past week, teachers have forced some bus lines to cancel trips to Oaxaca city, a popular tourist destination, and blocked a highway on the isthmus of Tehuantepec. Teachers maintain a protest encampment in the state capital's main square.
Unionized teachers have also blockaded streets, a shopping mall and train tracks in the western state of Michoacán.
