Talks aimed at easing Venezuela's economic and political crisis are threatening to run off the rails and could come to a head on December 6, opposition members warned Thursday.
The Vatican-backed "dialogue" aims to calm tensions as the center-right opposition demands a vote on removing Socialist President Nicolas Maduro.
It blames his management for the crisis driven by falling oil prices that has caused desperate shortages of food and medicine.
The opposition MUD coalition this week accused the government of boycotting the talks.
Some of its members threatened to do the same if the government does not agree at the next meeting on December 6 to let it have a vote.
"The government not only unilaterally froze the dialogue by not attending the talks on Tuesday, but also called into question the full meeting in December," said Jesus Torrealba, leader of the Democratic Unity Roundtable (MUD).
Another senior opposition leader, Henrique Capriles, alleged the government had skipped Tuesday's talks in pique after the opposition-led congress held a session on the conviction of two of his wife's nephews on US drug charges.
Maduro appeared on television shortly afterwards and insisted: "The dialogue continues to progress."
Opposition party Causa Radical, part of the MUD, called Thursday on prosecutors to investigate Maduro himself over possible complicity in the drugs affair.
That effort appeared unlikely to bear fruit because the high court has found in Maduro's favor in a string of rulings over recent months.
A survey by pollster Datanalisis in October indicated 78.5 percent of Venezuelans opposed Maduro's leadership.
Maduro has consistently resisted efforts to hold a recall referendum or early election. The opposition says he controls the courts and electoral authorities.
At the last round of talks on November 12, the sides made vague commitments to ease tensions and the food crisis. They have since accused each other of breaking their word.
"What is the point of this process if it yields no results?" Capriles said on Thursday.
"On December 6 we have to push for an electoral solution. We want a date. If not, I won't be coming to the party."