Authorities have raised a giant, iconic Mexican flag to half-mast in Mexico City's main square in commemoration of the 1968 massacre of student protesters by army troops 50 years ago.
Students and surviving leaders of the 1968 student democracy movement are planning marches Tuesday to mark the anniversary of an event that caused such revulsion it helped spur long-term political reforms.
It is unclear how many died in the nearby Tlatelolco plaza. Estimates range from the official version of 25 dead to a more recent investigation that identified 44. Activists at the time claimed hundreds, saying large numbers of bodies were carted off in garbage trucks.
The government at the time feared the students might try to disrupt the Olympic games held in Mexico City a few weeks later.
