Venezuelan President Nicolas Maduro on Saturday urged citizens taking part in a vote organised by the opposition the next day to do so "peacefully," as concerns simmered of worsening political violence.
The poll on Sunday is meant to gauge public support for a plan by Maduro to rewrite the constitution through the election on July 30 of a citizens' body.
But with authorities refusing to greenlight Sunday's vote and pro-Maduro supporters boycotting it, it looked likely to return a rejection of the president's scheme.
Likewise, the opposition has told its supporters to stay away from the July 30 election.
TRT World's Juan Carlos Lamas has more details from capital Caracas.
Fears of more protests
The cross-purpose initiatives have given rise to international worries — voiced by the Catholic Church and the head of the UN, Antonio Guterres — that the chances of bringing both sides together for dialogue has become more remote.
That, in turn, is stoking fears of more protests and running street battles with police, which have been persistent for the past three and a half months. Nearly 100 people have died in the unrest since the beginning of April.
While Maduro is deeply unpopular — with 80 percent of Venezuelans criticising his rein, according to the Datanalisis survey firm — he enjoys backing from some, mostly poor, parts of the population and, most importantly, from the military.
Many Venezuelans, though, are less focused on the political powerplay than they are on getting by day-by-day under their country's crushing economic crisis, which has meant shortages of food and medicine.
All 'ready' for vote
The opposition, which accuses Maduro of trying to gather dictatorial powers with the constitutional rewrite and other steps, said all was prepared for Sunday's vote.
"Everything is ready," one opposition figure, Maria Corina Machado, said.
She predicted Sunday's vote would "not only reject the Constituent Assembly" — the body Maduro is seeking to have elected to come up with a new constitution — "but will give a mandate for a change of the regime, the end of the dictatorship and the start of a transition with a government of national unity."
But Maduro, giving a national radio and TV broadcast, portrayed the vote as merely an "internal consultation by the opposition parties" with no electoral legitimacy.
"I call on all Venezuelans to participate peacefully in political events tomorrow, with respect for others' ideas, with no incidents. Peace is what I ask," he said.
He directed his followers instead towards a rival poll exercise that, unlike that of the opposition, has been approved by electoral authorities: a dry-run simulation of the election to take place on July 30.
He also repeated claims the opposition was tied to foreign powers — implied to be the "imperialist" United States — with the aim of toppling his government.
The international media, he railed, was covering the opposition vote in a way to justify foreign intervention.
According to Datanalisis, 70 percent of Venezuelans reject Maduro's idea of a Constituent Assembly.
An opposition leader, Henrique Capriles, said "we're expecting 62 percent turnout on Sunday — we could get 11 million people" out of the country's population of 30 million.
Five former Latin American presidents — from Bolivia, Colombia, Mexico and two from Costa Rica — were in Venezuela at the opposition's invitation to act as observers of the vote, alongside electoral experts from various countries.
Former Mexican leader Vicente Fox said on arriving in Caracas that the vote could be the "beginning of the end" of Maduro's government.
The head of the Organization of American States, Luis Almagro, called on Venezuelans to take part in Sunday's vote "to prevent the definitive collapse" of the country's institutions.
On Friday, UN Secretary General Guterres said talks were "urgently" needed between the opposition and government to stem the violence and find a "constitutional path" to peace.
Sunday's vote was being held in 2,000 polling stations across the country, and in 80 countries for Venezuelans abroad.