Violent clashes between police and members of a radical teachers' union left six people dead and more than 100 injured in southern Mexico's Oaxaca state.

The violence erupted as riot police moved in to dislodge protesters blocking a major road. Protesters threw stones and Molotov cocktails, and burned vehicles, while journalists saw riot police firing on protesters.

Mexico Oaxaca teachers protest
A riot police officer walks past a burning truck carrying chickensJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Chickens are seen on the road after a truck was set alightJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Riot police officers stand guard beside an overturned carJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
A riot police officer walks past a poultry truck that was set alightJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Riot police officers keep watch next to protesters from the National Coordination of Education Workers (CNTE) teachers' unionJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Riot police officers help an injured colleague during clashes with protestersJorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Jorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Jorge Luis Plata/Reuters
Mexico Oaxaca teachers protest
Patricia Castellanos/AFP
Mexico Oaxaca teachers protest
Patricia Castellanos/AFP
Mexico Oaxaca teachers protest
Patricia Castellanos/AFP
Mexico Oaxaca teachers protest
Pedro Armestre/AFP

The teachers from the National Co-ordinator of Education Workers, or CNTE, are opposed to the mandatory testing of teachers as part of Mexico's sweeping education reform and are also protesting the arrest of union leaders on money laundering and other charges.

Ten years ago, the teachers started a six-month takeover of Oaxaca that didn't end until police stormed the barricades.