Journalists Lucía Pineda, left, and Miguel Mora, center, celebrate their release from prison with Mora's wife, Veronica Chavez, at their home in Managua, Nicaragua, on Tuesday. (Alfredo Zuñiga/AP)

Nicaraguan authorities on Tuesday freed 56 people detained during a harsh crackdown on dissent last year, including leaders of a wave of anti-government protests and independent journalists.

The move was perhaps the most important in a series of releases of people considered political prisoners by the opposition. 

President Daniel Ortega had promised to free all such prisoners by June 18. His government has come under increasing international pressure, with the Trump administration steadily ratcheting up sanctions on his aides and family members. The European Parliament has also called for targeted sanctions on Nicaraguan authorities.

At least 324 people were killed, mostly by security forces and allied militias, as authorities crushed anti-government demonstrations last year, according to human rights groups. A report by an independent panel of experts backed by the Organization of American States recommended that Ortega and his security chiefs be investigated for crimes against humanity.

Ortega has denied the allegations and charged that the student-led protests amounted to a coup attempt

José Pallais, a spokesman for the Alianza Cívica opposition movement, said Tuesday that 89 political prisoners remained in jail and would probably soon be free. The group has said that more than 700 people were detained in the protests that began April 18, 2018. 

Among those freed early Tuesday were prominent figures in the protests, including Amaya Coppens, a student leader, and Medardo Mairena, a rural movement organizer. 

Also released were Miguel Mora and Lucía Pineda, who ran the cable news channel 100% Noticias. They had been detained in a police raid on their newsroom in Managua on Dec. 21 and became subjects of an international press-freedom campaign that included a full-page ad in The Washington Post this week. 

“We are going to have a free Nicaragua. Sooner or later, we will leave behind this dictatorship,” Mora said as he celebrated his release.

Human rights and press-freedom groups had protested that the prisoners faced charges such as “promoting terrorism” and “inciting violence” and were denied due process. Some were tortured, the groups said. 

The charges were dropped under an amnesty law passed last week that also shielded security forces from prosecution for their actions. 

“This law worries us because it could result in grave human rights violations in the country going unpunished and avert the establishment of truth, justice, reparation and guarantees this won’t happen again,” said Paulo Abrão, executive secretary of the Inter-American Commission on Human Rights. 

Francisco Aguirre Sacasa, a former Nicaraguan foreign minister, said Ortega had agreed to free the prisoners because of internal and external pressures. On June 20, a new U.S. law dubbed the “Nica Act” takes effect, which could expand sanctions and block assistance from international lending institutions. 

“By freeing the prisoners, they’re hoping to reduce international pressure,” the former minister said. 

Human rights activists are urging continued sanctions. José Miguel Vivanco, the Americas director at Human Rights Watch, said Ortega’s government needed not just to free prisoners but to also prosecute the pro-government forces that abused demonstrators.

“Not a single member of the police — not a single one — is under criminal investigation, much less charged or convicted of human rights atrocities” related to the protests, he said.

Ortega was a leader of the leftist Sandinista revolution that overthrew a right-wing dictatorship in 1979. He is in his third term as president since winning an election in 2006. Critics accuse him of becoming increasingly authoritarian. 

The government and opposition have held off-and-on negotiations since last year to seek a solution to the worst political crisis in three decades in this impoverished country. The latest round of talks broke down in March, with the opposition demanding the government free all political prisoners and allow peaceful marches, which had been banned since November.

The opposition is seeking early elections, but Ortega says he is determined to serve out his term, which ends in 2021. 

Mónica Baltodano, a former Sandinista guerrilla who is now an opposition activist, said the effort to oust Ortega would continue.

“We have to keep pressing in the talks for Ortega to leave and for early elections to be scheduled,” she said.

Sheridan reported from Mexico City.