Updated

Three men have been killed amid a government crackdown on student protesters holed up in universities in Managua, the Nicaraguan capital.

Nicaragua's official news site El 19 Digital named the victims as Carlos Alberto Miranda, 19; Kevin Joel Valle, 19; and Alejandro Estrada Vega, 53. It attributed their death to "gang members of the right."

Assistant police commissioner Francisco Diaz denied any police presence near the university campuses in an interview with local radio.

But The Associated Press confirmed the mobilization of riot police around the Polytechnical University and National University.

The protests began in April as students demonstrated against a social security reform. Many are now demanding that President Daniel Ortega and his wife Rosario Murillo leave office.

Before the additional deaths Thursday, human rights groups estimated 63 people had been killed.