President Nicolas Maduro urged his armed forces Wednesday to be on guard following news reports in the United States that a year ago President Donald Trump raised the possibility of invading Venezuela.

Venezuela's languishing currency, the bolivar, has officially slid 86.6 percent against the euro according to a new auction of the European currency by Venezuela's central bank, whose result was given Monday.

Three major opposition parties in Venezuela have announced they will boycott municipal elections in December, saying the vote will not be free or transparent.

"Taking part in these elections is not viable," said Henry Ramos Allup of Democratic Action, one of those three parties. The voting is scheduled for December.

The widespread rights abuses committed against protestors in Venezuela indicate that the country has implemented a policy of repression aimed at instilling fear in the population, the U.N. said Wednesday.

A fresh U.N. report warned that the rights situation in Venezuela was at "grave risk" of unraveling further as the authorities continue to systematically and brutally repress demonstrators, and urged international action.

Venezuela's all-powerful new constituent assembly said Tuesday it will hold treason trials for opposition leaders it said are promoting economic sanctions imposed by the United States.

The assembly approved a decree in which it announced a "historic" trial against "those who involved in promoting these immoral actions against the interests of the Venezuelan people."

U.S. Vice President Mike Pence on Wednesday vowed the U.S. would not allow "the collapse of Venezuela," saying such an event would "endanger" countries in the wider region.

"The collapse of Venezuela will endanger all who call the Western Hemisphere home," Pence said in remarks delivered before some 600 people at a Catholic church in Doral, the heart of Miami's Venezuelan community. 

Venezuela's fugitive former top prosecutor resurfaced in Brazil on Wednesday claiming to possess "a lot" of proof of President Nicolas Maduro's corruption and warning that her life remains in danger.

Days after a dramatic escape from chaotic Venezuela, Luisa Ortega, 59, turned up the heat on Maduro, who has asked Interpol to issue a "red notice" warrant for the arrest of his critic.

Nicolas Maduro's government in Venezuela is increasingly isolated but it still counts powerful support from countries such as Russia and China that can block or delay punitive action from the likes of the United Nations, analysts say.

Venezuela held elections Sunday for a Constituent Assembly backed by embattled President Nicolas Maduro to rewrite the constitution. Opposition activists and some foreign countries have doubts. What do we know -- and not know -- about the vote?

- What we know -

Venezuela's top court failed to meet a Wednesday deadline on whether to suspend Attorney General Luisa Ortega -- one of the most prominent detractors of President Nicolas Maduro -- and put her on trial.

Ortega, 59, is the most senior figure to defy Maduro as he fends off efforts to remove him from power in the volatile oil-exporting nation which has been gripped by more than three months of deadly unrest amid a desperate economic crisis.