Some members of Venezuela's divided opposition began talks with the government Sunday night as part of a Vatican-led attempt to defuse the country's political crisis ahead of another big street protest to call for the removal of socialist President Nicolas Maduro.

Maduro arrived at a museum in western Caracas to formally kick off the talks, which many of his foes fear could be a stalling tactic designed to ease pressure on the leader who is widely unpopular over rocketing inflation and shortages of food and other basic goods.

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.

The talks come as the opposition is stepping up its campaign seeking to force Maduro from office.

Last week it rallied tens of thousands of supporters across the country and another protest has been called for Thursday for which the opposition is vowing to march to the presidential palace. Government foes haven't 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.

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 doesn't 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 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, where he was joined by former presidents of Spain, Panama and the Dominican Republic and a Vatican mediator.

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.

Archbishop Claudio Maria Celli, a Vatican envoy to the talks, hailed the start of latest round of talks 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."