MEXICO CITY -- Police and students at a rural teachers' college in southern Mexican clashed Sunday leaving eight people injured in what authorities said was an operation to clear a road blockade and students called an unprovoked attack.
The confrontation outside the Mactumactza Normal Rural school in Tuxtla Gutierrez, the capital of Chiapas state, came during a visit by the parents of 43 students from the Ayotzinapa teachers' college in Guerrero state who disappeared in 2014 in what has become a symbolic human rights case in Mexico.
Authorities said two police officers were injured in Sunday's clash. A human rights group said three students, two mothers and a 3-year-old girl were also hurt.
The Chiapas prosecutor's office said in a statement that it was investigating what happened.
The two sides offered widely different versions of events.
The ministry of public security said riot police cleared a road blocked by students who had assaulted two police officers, vandalized a patrol car and threw Molotov cocktails and stones at the officers.
The human rights group Tlachinollan, which serves as a speaker for the parents of the 43 missing students, said the protest was scheduled for Sunday afternoon and had not yet begun when a large contingent of riot police arrived.
The police began to hurl tear gas at the students “without any valid explanation,” it said in a press release.
The National Human Rights Commission called the police action repressive.
"There is no room for any expression that violates the right to free expression even less so if violent and repressive methods are used,” the commission said in a statement.
Students at Mexico's rural teachers' colleges have held many protests for an assortment of reasons over the years.
In the Ayotzinapa case, authorities say leftist students were abducted by police in the town of Iguala in September 2014 and handed over to the drug gang Guerreros Unidos.
Jesús Murillo Karam, attorney general under then-President Enrique Peña Nieto, infamously announced the "historic truth" about the students' disappearance — that they were killed and their bodies incinerated at a garbage dump. But independent experts said there was no evidence to support the conclusion that the bodies had been burned there.
Parents of the disappeared have asked President Andrés Manuel López Obrador to initiate criminal proceedings against officials, ramp up collaboration between prosecutors and a truth commission, and require the army to answer more than 100 unanswered questions.