A stampede at a university in Bolivia Monday left four students dead and more than 70 injured when a tear gas grenade was detonated during an assembly, the institution and police said.

Five of the injured were in intensive care, said Roxana Choque, public prosecutor of the Potosi region in Bolivia's southeast where the Tomas Frias university is based.

Hundreds of students had gathered in an enclosed sports arena of the university for student council elections, rector Pedro Lopez told reporters.

A heated debate ensued, and at least one student detonated a tear gas cannister, provoking the stampede, according to regional police chief Bernardo Isnado.

The institution, Lopez added, was "in mourning."

Two suspects have been arrested, said police official Nelson Pacheco. One is a student leader involved in convening the assembly and the other is suspected of actually setting off the tear gas grenade, he said.

Choque said many of the wounded had suffered multiple injuries, including broken bones, and the deceased had died of asphyxiation.

The public hospital of the city of some 270,000 inhabitants was overrun with wounded and relatives seeking information on missing students.

A woman, who did not give her name, sobbed as she told local media her daughter was in intensive care.

"Are they going to give me my daughter alive?" she asked through tears.

"Please be patient. The hospital is overrun. There is no space," an official of the institution urged dozens of family members jostling for space and news.

The government has announced an investigation into the events.

Fights between students in Bolivia are not uncommon, and tear gas had been deployed in previous confrontations.

In March last year, 12 students died at a different university when a railing collapsed during another assembly confrontation.