Mexico City, In an incident a violent clashes occured between teachers opposing an education overhaul, and security forces in Mexico's Oaxaca state, in which atleast three persons were killed.

The state government, in a statement confirmed the deaths in the clashes on Sunday in Asuncion Nochixtlan with 45 others injured.

When federal and state law enforcement officers moved in to clear a roadblock set up by members of Local 22 of the teachers union on the Oaxaca-Puebla federal highway in that municipality, then the clashes started.

The clashes lasted for more than 2 hours in which several injured by stones and other projectiles and firearms. 

"At least six police officers were injured by gunfire, one of whom suffered head trauma, and 21 people were arrested", said Oaxaca authorities.

Authorities further added, that "the teachers torched a truck to prevent officers from advancing, regrouped after being dislodged and set up a new roadblock in the same area. They also overturned official vehicles".

The 2013 education overhaul implemented by President Enrique Pena Nieto's administration, has been opposed by the teachers union, a powerful labour organisation with 200,000 members.