Several thousand students marched through Mexico City to mark the anniversary of a 1968 massacre in which troops fired on protesters at the capital's Tlatelolco Plaza, killing an unknown number.

Violence that often marks the annual demonstration was avoided Sunday, with police guarding the march route and steel and wood barriers protecting businesses that are often vandalized.

This year's march comes as radical rural teachers' college students have battled authorities, blocking highways, hijacking and burning vehicles and kidnapping police in the western state of Michoacan, to demand teaching jobs.

Paula Rodriguez was one of the teachers' college students from Michoacan marching Sunday. In her words, "We have been subject to repression ... because the government doesn't want the teachers' colleges to exist."