The socialist leader met opposition leaders at the weekend in talks convened by the Vatican, but they conditioned further dialogue on the release of political prisoners and a national vote on Maduro’s rule.
His adversaries accuse Maduro of creating a dictatorship by leaning on compliant institutions to block a recall referendum on his rule and sideline the opposition-led legislature.
Authorities freed the three activists — Carlos Melo, Andres Moreno and Marco Trejo — on Monday night, but the opposition says another 100 or so Maduro opponents remain in jail.
“I hope that what happened to me, will happen to all of them,” Melo said in a video released after his release.
He was detained in August and accused of carrying explosives as part of a coup plot against Maduro.
Moreno and Trejo spent a month in jail, accused of damaging military morale in a political propaganda video that showed a soldier suffering the same economic hardships as protesters.
“These (releases) were decisions by the tribunals in the context of the dialogue process, gestures,” said senior Socialist Party official Jorge Rodriguez, who is representing the government in the talks.
He added that investigations of the three activists were continuing.
They deny the charges, and opposition parties say they were trumped up as part of a wave of repression this year.
Jesus Torrealba, secretary-general of the Democratic Unity coalition, said the releases were welcome but not enough given scores remained in detention including well-known opposition leaders Leopoldo Lopez, Antonio
Ledezma and Manuel Rosales.
“The releases have to continue. They must give us the recall referendum back, or if not, bring the presidential elections forward,” he said on a radio programme.
Venezuela’s next presidential election is due in late 2018.
Maduro, who is struggling to control shortages of consumer goods and soaring prices in an unraveling economy, says he is a victim of opposition conspiracies to overthrow him and of an “economic war” led by businesses with the backing of Washington.