In an address on social media, Guaido urged the military high command to join a "unity pact" of opposition forces to block the holding of the December 6 polls.

"Stop hiding behind the dictator's skirts, stop ignoring the reality in Venezuela," Guaido said in a message addressed to the high command, considered the main pillar of Maduro's rule, along with allies Russia and Iran.

"We are willing to sit down once again with those who are needed to achieve a transition," Guaido said.

In January 2019, National Assembly speaker Guaido challenged Maduro's authority by declaring himself acting president, claiming that Maduro had stolen his 2018 re-election in a rigged vote.

Since then the opposition has tried unsuccessfully to displace Maduro, including an abortive April 2019 military uprising organized by Guaido which failed to muster much support.

Guaido and leading opposition figures vowed to boycott the December 6 elections over a lack of transparency after the Maduro-friendly Supreme Court appointed election officials -- a role that should have been conducted by the opposition-controlled legislature.

Some 37 opposition parties are backing the election boycott and a so-called pact proposing to "increase international pressure against the dictatorship," according to Guaido.

However, some prominent opposition figures, have spoken out in favor of participation in the polls, including Henrique Capriles, a widely-respected figure who has twice run for the presidency.

Another prominent opposition lawmaker, Stalin Gonzales, also publicly split from the pro-boycott group last week, saying that mobilizing opposition at the ballot box would be more effective than a boycott.

Maduro's socialist government is targeted by a slew of international sanctions, including a US oil embargo, and he and his close associates are under indictment for drug trafficking by the US Department of Justice.

Venezuela is sitting on the world's largest proven oil reserves but under Maduro's watch, the country has descended into crisis.

Poverty has soared, inflation is the highest in the world, and oil production is down to its lowest level in 77 years, which experts blame on mismanagement and corruption.