Thousands of masked protesters who had gathered in Mexico City to commemorate the 47th anniversary of a student massacre that took place in 1968 fought with riot police on Friday.

The AFP reports that during an hour of violent disorder around 300 so-called "anarchists" tossed stones and firebombs at the officers guarding the National Palace. The protestor’s actions, which took place in Zocalo square, were met with tear gas and resulted in three arrests.

Meanwhile, in the city of Oaxaca, 52 masked youths were arrested for vandalizing stores and banks.

The 1968 massacre was the end of a short-lived student protest movement in which students were calling for an end to perceived repression. Ten days before the opening of the Summer Olympics in Mexico City, police officers and military troops shot into the throngs of unarmed students. The actual number of causalities remains a mystery. As NPR reports, the number of deaths reported has ranged between four to 3,000.

Friday's clash with the riot police led to calls for restraint from organizers of the rally. More than 15,000 people joined in solidarity.

Last November, tens of thousands of protesters took to Zocalo square to voice their rage and frustration over the disappearance of the 43 college students who went missing in the state of Guerrero. The demonstrations, which had started out peacefully, ended in a confrontation between police and protesters.

The New Yorker reported that in the wake of the missing students, Mexico was experiencing marches and protests on nearly a daily basis. A frequent chant among the wary demonstrators was “The state is dead.” 

As quoted in CNN, a marcher participating in November's Zocalo protest said, "The problem isn't just the 43 students, it's the thousands more that disappeared before them."

"We're not going to be quiet any longer," added the marcher.