Student protesters are calling for action across Mexico on Wednesday of this week after the discovery of mass graves suspected to be of murdered student activists.
Police arrested 43 students in the state of Guerrero on 26 September. The students then disappeared.
At least 34 bodies have been found in six different graves in the area.
Family members and other students accuse the authorities of handing over arrested activists to organised criminal gangs to be assassinated.
The students have been taking part in a mass campaign against free market attacks on education.
Tens of thousands have joined strikes and protests since 24 September.