Venezuelan President Nicolas Maduro was to install a powerful new assembly of his allies on Friday, dismissing an international outcry and opposition protests saying he is burying democracy in his country.
The Constituent Assembly, elected last weekend in a vote marred by violence and allegations of fraud, will sit in a chamber in the Legislative Palace in Caracas, where the opposition-controlled legislature is located.
The inaugural session of its 500-plus members, who include Maduro's wife and son, will take place under high tension.
The opposition has called a mass march in the capital, raising fears of violence that could add to a death toll of more than 125 over the past four months.
"Let there be no provocations, nor should people fall into provocations," Maduro said late Thursday as he assured all was ready for the Constituent Assembly.
The Vatican on Friday urged the inauguration of the new assembly be suspended. It also appealed for Venezuelan security service to show restraint.
Meanwhile, Venezuela's intelligence service unexpectedly transferred a high-profile opposition figure, Caracas mayor Antonio Ledezma, from jail to house arrest, his wife said.
Ledezma and another opposition figure, Leopoldo Lopez, had been taken from their homes to military prison on Tuesday, reversing earlier home detentions. Lopez remains incarcerated, one of hundreds of what the opposition called political prisoners.
The Constituent Assembly marks a new stage in Venezuela's rule.
With unlimited powers to dissolve the National Assembly or amend laws, the new body is tasked with rewriting the 1999 constitution brought in under Maduro's late mentor and predecessor, Hugo Chavez.
Maduro claims its work will yank Venezuela out of its worsening spiral of political and economic crisis, though he has not detailed how. Nor has he given an end-date for the Constituent Assembly, which he said would operate for years.
The body is being challenged on several fronts.
Backing opposition allegations of fraud, Smartmatic, a British-based company involved in the vote technology behind the election last Sunday, said the official turnout figure had been tampered with and exaggerated by at least a million voters.
Although brushed off by Maduro as part of a plot by "the international enemy," that gave grounds for Venezuelan Attorney General Luisa Ortega, a thorn in Maduro's side, to order an investigation.
She said prosecutors had lodged court cases seeking to have the Constituent Assembly annulled, though few in Venezuela believed that would be achieved.
The country's supreme court has systematically sided with the president in blocking prosecutorial or legislative gambits against the government.