Anti-government protests erupted in Nicaragua last month.
CNN  — 

A human rights watch group is accusing Nicaraguan authorities of using excessive force, threats and torture against demonstrators since protests began in the country last month.

In a preliminary report, the Inter-American Commission on Human Rights says at least 76 people have been killed and 868 injured in anti-government protests.

According to the Nicaraguan government, the death toll is 13. CNN has reached out to authorities for comment and has not yet received a response.

The rights group, known as IACHR, is calling on Nicaraguan officials to ban the use of lethal force against protesters after it found evidence that police “used firearms, rubber bullet guns and tear gas indiscriminately to dissolve protests and demonstrations.”

“Potentially lethal force cannot be used to maintain or restore public order. Only the protection of life and physical integrity before imminent threats can be a legitimate objective to use such force,” the IACHR said.

In addition, the group is reporting that 438 people including students, civilians, activists and journalists have been detained in connection with the unrest.

Protests began April 18 when President Daniel Ortega tried to change the country’s social security system. He implemented a controversial pension reform resolution intended to halt the growing deficit. The changes increased contributions by workers and employers and reduced retired workers’ pensions.

Violent protests stopped as Ortega subsequently reversed the reforms, but the unrest continues.

The IACHR condemned actions against protesters, and urged officials to investigate and hold those responsible accountable.

The group is also calling for “measures to guarantee the free and full exercise of rights to freedom of expression, peaceful assembly and political participation,” decrying censorship of media outlets, noting some were shut down for days.

Nicaraguan Foreign Minister Denis Moncada said in a news conference on Monday that the government will study the IACHR report and will maintain communication with the organization’s representatives.

Protests continue amid negotiations

More than a month since protests erupted in Nicaragua, authorities and various sectors of society are in negotiations with the country’s Catholic Church as their mediator.

Lesther Alemán, a student leader, said the dialogue wasn’t for compromise but rather for negotiating Ortega’s exit.

“You know very well what we have lived,” Alemán said, speaking to Ortega. “This isn’t a table for dialogue, this is a table to negotiate your exit and you know this very well.”

First lady and Vice President Rosario Murillo continues to reaffirm the government’s commitment and openness to the dialogue, saying officials are “united in prayer for the recuperation of peace and new directions,” according to state run news Digital 19.

CNN’s Nicole Chavez and CNN en Español’s Samantha Lugo, Ana Melgar, Abel Alvarado, Juliana Gonzalez, Elizabeth Plaza and Daniel Silva Fernandez contributed to this report.