By Andrew Cawthorne and Diego Oré
CARACAS (Reuters) - Venezuela has freed a politician accused of fomenting violent protests in 2014, but opposition leaders said on Friday it was not enough and demanded President Nicolas Maduro's government release all 100 or so jailed opponents.
The liberation of Rosmit Mantilla, a well-known activist for the hardline Popular Will party, came amid Vatican-brokered talks between the socialist government and the opposition that are focusing on prisoners among other issues.
"I remain hopeful my comrades still behind bars will be freed soon," Mantilla, 33, told reporters after being released and going straight to hospital for gall bladder surgery.
"It was a tough time ... Now I'm going home to be with my family, I want to take a few days, after the operation, but my commitment remains strong for all Venezuelans' freedom."
Mantilla, who was studying journalism alongside his political activism, was arrested at his grandparents' apartment in May 2014, accused of helping finance anti-Maduro protests that led to violence and 43 deaths that year.
During months of riots, the fatalities included both opposition and government supporters, and security personnel.
Supporters say authorities framed Mantilla by placing envelopes with money in the apartment. From prison, Mantilla won election as a substitute legislator in a vote last year when the opposition took control of Venezuela's National Assembly.
Maduro, the 53-year-old successor to Hugo Chavez whose popularity has dived during an unprecedented economic crisis, accuses foes of seeking a coup against him and denies the existence of political prisoners.
Officials often recall a short-lived 2002 coup against Chavez, and display arms, explosive materials, cash and messages as evidence of the crimes of radical activists.
Amnesty International welcomed Mantilla's release, saying he was victimized for rights work. "He should have never been made to spend a second behind bars. The Venezuelan authorities must now build on this positive step and release all imprisoned activists and political leaders whose only 'crime' was to disagree with the government," it said.
That was echoed by opposition leaders, who call Maduro a dictator. "We must keep demanding the release of the other political prisoners, the return of our exiles and an end to persecution," a Popular Will leader, David Smolansky, said.
Local rights group Penal Forum says that after Mantilla's release, Venezuela still holds 108 political prisoners, and is using them as chips in the Vatican-mediated negotiations.
The opposition coalition puts the number higher at 135.
Three activists were released in an early gesture soon after talks began last month.
(Additonal reporting by Camilo Cohecha; Editing by Alexandra Ulmer and Phil Berlowitz)