Ex-Chavez challenger Manuel Rosales released

Venezuela's government has released a former presidential candidate from jail, as well as five other activists considered to be political prisoners.

Manuel Rosales was imprisoned in October 2015 on charges of illicit enrichment upon returning to Venezuela after six years of exile in Peru.

Rosales, former governor of Zulia state, who challenged then-president Hugo Chavez in 2006, was released before dawn on Saturday, along with five activists who were jailed during anti-government protests in 2014.

"I have been freed, along with other political prisoners," Rosales wrote on Twitter.

Opposition groups said that those freed in addition to Rosales were Skarlyn Duarte, Yeimi Varela, Nixon Leal, Angel Contreras and Gerardo Carrero.

Carrero is a prominent activist who led a group of students who camped for weeks outside the UN offices in Caracas to draw attention to a government crackdown on protests blamed for scores of deaths.

But Rosales remains under house arrest and the five others released still face charges arising from their activities in 2014, for which they will have to periodically present themselves to judicial authorities.

"We will continue to fight for the liberation of everyone," Rosales said.

The releases come as a two-month-old, Vatican-mediated attempt at dialogue to ease tensions fuelled by the country's deep economic and political crisis hangs by a thread.

New round of protests

President Nicolas Maduro has refused to cede ground to opponents seeking his removal. With many in the opposition pushing for a new round of street protests, the Democratic Unity alliance has said it will participate in the next scheduled meeting on January 13 unless the government meets its demands.

Those include releasing more than 100 people it considers to be political prisoners and naming a new board to the government-controlled electoral council.

Venezuela's political crisis has been intensifying since authorities in October blocked an opposition effort to collect signatures and force a recall vote against Maduro.

But even many poor Venezuelans, who traditionally formed the base of the revolution started by the late Chavez, have abandoned their support for the government amid triple-digit inflation and widespread shortages that have made putting food on the dinner table an all-consuming, daily ordeal.