Members of Venezuela's opposition have met the government for talks as President Nicolas Maduro seeks to fend off calls for his removal.
Maduro launched the talks on Sunday night at a museum in western Caracas, held in the presence of mediators from the Vatican and former presidents of Spain, Panama and the Dominican Republic.
Some of Maduro's rivals fear they could be a stalling tactic designed to ease pressure on the unpopular socialist leader, who many Venezuelans blame for triple-digit inflation and widespread food and medicine shortages.
Fifteen parties belonging to the Democratic Unity opposition alliance boycotted the talks, saying they were not prepared to sit across from the government until it released several jailed opposition activists and reversed its decision to cancel a constitutionally allowed recall referendum against Maduro.
"For an eventual dialogue to take place it has to be very clear from the outset that the aim is agreeing on the terms of a democratic transition in the remainder of 2016," the parties said in a statement.
Archbishop Claudio Maria Celli, the Vatican's envoy to the talks, praised the dialogue as something "very positive".
He urged both sides to make concessions in order for the talks not to falter like the previous attempts.
"At the start of this journey, I ask you in the name of Pope Francis that each side agrees to some concrete gestures to give credibility to this process," said Celli, who is president of the pope's council for social communications.
"The country is waiting for authentic signals to comprehend that dialogue is a reality."
Last week the opposition alliance rallied tens of thousands of supporters across the country and another protest has been called for Thursday for which the opposition is pledging to march to the presidential palace.
Government's critics have not been allowed to get close to the palace since the 2002 coup that briefly toppled President Hugo Chavez, the late leader who installed the socialist administration.
In recent weeks the opposition has been stepping up its campaign seeking to force Maduro from office.
The opposition-controlled congress, meanwhile, has begun a "political trial" against Maduro accusing him of neglecting his duties, though it is a largely symbolic gesture since the body does not have the power to remove a president under Venezuela's constitution.
Although he has threatened to arrest legislators if they go ahead with the trial, Maduro said on Sunday night that he has an "absolute commitment" to holding a dialogue with the opposition.
"We're giving a chance to disarm the hatred, the intolerance, and open the door to love among the Venezuelans," he said in televised remarks from the museum.
Previous attempts have been made at having a dialogue between the opposition and the government, such as talks that followed a wave of deadly unrest in 2014.
Those sessions calmed the streets but failed to produce any meaningful progress on key issues dividing Venezuelans.