Clashes between police and a teachers' union turned violent in Mexico on Sunday (June 19) leaving six people dead, according to state officials. Fifty three civilians, 41 federal police agents and fourteen state police agents were also injured in the incident.

The conflict between police and the teachers' union Coordinadora Nacional de Trabajadores de la Educación (CNTE) took place in the state of Oaxaca. The union was protesting against the arrest of their leader Rubén Núñez and seven others in recent weeks.

The CNTE, which has a history of radical activism, was also protesting against the education reforms introduced by President Enrique Pena Nieto in 2013. The new reforms include mandatory evaluation of teachers' performance.

The union blocked roads and malls and also forced some bus lines to cancel trips to Oaxaca.

According to Mexican authorities, the protest turned violent when gunmen from outside started firing at both sides in order to create commotion and divergence.

The statement from Mexico's federal government says, "The attacks with guns came from people outside the blockades who fired on the population and federal police." It also states that the police officers who were trying to clear roads during protests were not carrying guns.

Núñez was arrested on 12 June over money laundering and corruption charges. His union believes he was duped in a political game, with some describing him as a "political prisoner" and "hostage of the federal government".

However, federal prosecutor Gilberto Higuera, claimed: "He raised more than 24m pesos ($1.3m; £900,000) illegally between 2013 and 2015," reported BBC.

Francisco Villalobos, Nunez's deputy, was also arrested last week for allegedly stealing textbooks.