The Nicaraguan government has released 30 people who were detained during anti-government protests on Sunday.
Their arrests gave rise to criticism from human rights groups and the Organization of American States (OAS) regional body.
The leader of a group critical of President Daniel Ortega said it was clear that no evidence had been found against those detained.
Police had argued that the protesters had not sought permission to march.
They confronted the demonstrators on Sunday and fired stun grenades.
Anti-government protests were declared illegal by President Ortega on 28 September following five months of often violent clashes during which hundreds of people were killed.
The protesters detained on Sunday had defied the ban and gathered in the capital, Managua, under the motto “United for Liberty”.
They were confronted by riot police and 38 of them were arrested. All 38 have since been released but hundreds detained in other protests still remain behind bars, human rights groups say.
Some of those leaving El Chipote maximum security jail raised their fists in a show of defiance and shouted: “Long live free Nicaragua!”.
Their relatives had gathered at the offices of local human rights groups to call for their speedy release.
Their call was backed up by the head of the OAS, Luis Almagro, and the president of neighbouring Costa Rica, Carlos Alvarado.
The Nicaraguan government did not comment directly on the release of those detained but in a speech broadcast on Monday, Vice-President Rosario Murillo said that “all Nicaraguans want peace”.
The current wave of protests first kicked off in April when demonstrators demanded that planned changes to the country’s social security system be shelved.
Following deadly clashes between the security forces and the demonstrators, the protests soon escalated and the protesters demanded that President Ortega step down.
Mr Ortega has been in power since 2007 and his critics accuse him of becoming increasingly authoritarian and restricting Nicaraguans’ freedoms and civil liberties.
The president in turn accuses the protesters of planning a coup against his democratically-elected government and of incitement to violence.
Local human rights groups as well as the United Nations Office for Human Rights have documented alleged human rights violations which range from illegal detention to torture.