Mexico has ordered dozens of military personnel to be arrested for suspected involvement in the disappearance of 43 students from a teacher's college six years ago, in an unresolved case that outraged the country.
The arrest warrants were announced by President Andres Manuel Lopez Obrador on Saturday as he presented a report on a lengthy investigation into the tragedy.
"Those proven to have participated will be judged," he said at an event with parents of the missing students
The president did not detail any charges against the suspects.
The disappearance of the students in southern Gurerro state sent shockwaves around Mexico.
They had commandeered five buses to travel to a protest, but were stopped by corrupt police officers in the city of Iguala, Guerrero and handed over to a drug cartel.
Prosecutors initially said the cartel mistook the students for members of a rival gang and killed them before incinerating their bodies at a garbage dump and tossing the remains in a river.
An official report presented in January 2015 by the government of then president Enrique Pena Nieto was rejected by relatives of the students as well as independent experts from the Inter-American Commission on Human Rights.
Pena Nieto had strongly opposed interrogating military personnel or calling them to testify.
Nearly three dozen people allegedly involved in the case have been arrested since March, officials said.
Families of the victims have long complained that the military did nothing to protect the students and may even have been accomplices in the crime.
Speaking for relatives on Saturday, Maria Martinez Zeferino -- the mother of one of the missing students -- thanked the president but urged him to move faster in hopes that some of the disappeared may still be alive.
In the afternoon more than 5,000 people led by the parents marched in downtown Mexico City, chanting slogans such as "They took them alive, we want them back alive!" and "Justice!"
One group that joined the tail end of the march smashed windows and clashed with riot police, injuring at least one officer.