Thousands of teachers protested in southern Mexico on Monday to denounce a "massacre" a day after at least eight people died during violence authorities blamed on unidentified gunmen.
A teachers union organized the demonstration in the tourist city of Oaxaca to demand justice for the deaths during a protest on Sunday, while some 15 masked protesters launched fireworks at police during Monday's march.
The National Education Workers Coordinator (CNTE) union has been leading demonstrations across the state of Oaxaca against an education reform and the arrest of two of its leaders.
Six people died and more than 100 were injured, including officers and civilians, when police were deployed to break up a week-long road blockade by the CNTE in Asuncion Nochixtlan, near Oaxaca city.
Federal police chief Enrique Galindo said unidentified gunmen opened fire on the population and the police but that teachers were not involved in the shooting.
The National Security Commission had initially denied that police were armed during the clashes, charging that news pictures showing officers with firearms were "false."
But Galindo said officers were forced to use weapons after they were "ambushed" by 2,000 "radicals," including some of whom were armed.
Galindo told Radio Formula that "autopsies are being conducted" to determine if any of the dead were hit by police bullets.
Officials said eight police officers had gunshot wounds. At least 55 officers and 53 civilians were injured in the clashes, while more than 20 people were arrested.
A journalist, meanwhile, was shot dead by unknown gunmen after taking pictures of looting in the town of Juchitan. An eighth person was killed in the same town, said Oaxaca state security chief Jorge Alberto Ruiz.
Authorities had previously given a death toll of six but Ruiz told MVS radio that the deaths in Juchitan were "linked" to the unrest.
- 'Radicals' or 'infiltrators'? -
The government said the teachers did not fire weapons and that the violence was perpetrated by other groups.
The six dead include two shopkeepers, a farmer, a worker, a student and a local official, Governor Gabino Cue said.
Juan Garcia, a leader of the Section 22 of the CNTE union reported that 22 other people were missing.
Garcia said the violence was perpetrated by "infiltrators" and that the union was calling for Cue's resignation.
Garcia also asked for an investigation by the Inter-American Commission on Human Rights and charged that police "fired without mercy."
- Past violence -
The CNTE has staunchly opposed Pena Nieto's education reform, which requires teachers to undergo performance evaluations.
The union has also been protesting last weekend's arrest of the leader of its Section 22 in Oaxaca, Ruben Nunez, and his deputy, Francisco Villalobos. Nunez faces money laundering charges, while Villalobos has been accused of stealing textbooks.
Radical teachers have held protests against the reform in Oaxaca and the southern states of Michoacan, Guerrero and Chiapas for months.
The government says the reform seeks to improve the quality of education, but the union sees it as an attempt to fire teachers and privatize education.
The unrest comes a decade after protests by the CNTE and other local civil organizations were marked by deadly violence.
Around 20 people died in the upheaval between 2006-2007, including US cameraman Brad Will, who was killed during a protest.
A truth commission recently concluded that Will's death was an "extrajudicial killing." The commission also documented cases of torture and forced disappearances committed by security forces.
