A group of masked and self-declared "anarchists" clash with the federal police at Zocalo square in Mexico City on 2 October, 2015 after a demonstration to commemorate the 47th anniversary of a 1968 massacre of students (AFP)
Masked protesters clashed with riot police in Mexico City on Friday after thousands of people marched to commemorate the 47th anniversary of a student massacre.
Three people were arrested in the hour-long violence in Zocalo square during which about 300 self-styled "anarchists" lobbed stones and firebombs at police guarding the National Palace, who responded by firing tear gas.
The clashes triggered calls for restraint from organizers of the rally, which drew more than 15,000 people, mostly students.
Separately, there was a similar protest in the city of Oaxaca, in the south of Mexico, where local authorities said 52 masked youths were arrested for offenses including vandalizing shops and banks.
The march marked the anniversary of a 1968 massacre of students by the army in the Tlatelolco neighborhood in the capital in the lead-up to the Olympics in Mexico City.
The students had been demanding an end to repression and civil society groups say the official death toll of about 40 was in fact much higher.