At least three people were killed in southern Mexico during clashes protesting teachers and police, reports Bi-bi-si.
Another 45 people, including police officers, were injured.
The incident took place in Oaxaca on Sunday, June 19. The reason for the demonstration was the arrest last week of two heads of the trade Union of education workers (CNTE), accused of corruption.
Protesting against the arrest of their leaders, trade Union activists blocked roads. Authorities claim that the attempt of the police to clear the way unknown opened fire as the demonstrators and the police, creating chaos.
The national security Commission of Mexico said that the police had not used the weapon.
CNTE opposed education reforms that President Enrique peña Nieto began in 2013. Changes include new methods of teacher assessment.