The death toll from violent protests in Mexico’s southern state of Oaxaca rose to 10 on Monday as the authorities vowed to investigate whether police were responsible for any deaths.

The death toll from violent protests in Mexico's southern state of Oaxaca rose to 10 on Monday as the authorities vowed to investigate whether police were responsible for any deaths.

Seven civilians died of bullet wounds in Asuncion Nochixtlan and another person was killed by an explosive, Oaxaca chief prosecutor Joaquin Carrillo said.

Officials had earlier reported six deaths in Asuncion Nochixtlan, where police said they were ambushed by an unidentified armed group after officers removed barricades set up by teachers protesting an education reform.

None of the dead were teachers, Carillo said.

Federal police chief Enrique Galindo said officers were deployed to remove the weeklong road blockade, but that armed police were sent after the unidentified civilians opened fire.

Officers will give statements to prosecutors as part of the investigation to determine "who started or didn't start (firing)," he told a news conference.

Interior Minister Miguel Angel Osorio Chongo said the investigation will seek to determine if "the use of weapons by the state and federal police was adequate or not, who did it, who ordered it" and if it respected official protocol.

Elsewhere on Sunday, unknown gunmen in Juchitan shot dead two other people, including a photojournalist who took pictures of looting amid protests.

The radical CNTE teachers union led a mostly peaceful protest on Monday in Oaxaca's capital to denounce what it called a "massacre."

The union has blocked roads in protests against President Enrique Pena Nieto's education reform, which requires educators to undergo performance evaluations.

Teachers have also held protests in the southern states of Michoacan, Guerrero and Chiapas.