The U.S. on Wednesday threw its full support behind an ongoing military uprising aimed at ousting Venezuelan President Nicolas Maduro from power.

"Today interim President Juan Guaido announced start of Operacion Libertad, " Mike Pompeo said on Twitter. "The U.S. Government fully supports the Venezuelan people in their quest for freedom and democracy. Democracy cannot be defeated."

Guaido earlier published a video alongside a small contingent of uniformed military personnel and armored vehicles in which he called for an uprising to end the "usurpation" of Maduro.

He stressed this was the beginning of the final phase of the effort to oust Maduro, known as Operacion Libertad, or Operation Liberty. 

"The National Armed Forces have made the correct decision, they have the support of the Venezuelan people," Guaido said.

Guaido also called on the Venezuelan people to take to the streets to support the "democratic forces" and "recover the country's freedom" after sympathetic military officials released Leopoldo Lopez, the opposition leader who has been held in custody since 2014 for leading anti-government protests.

Venezuela has been rocked by mass demonstrations since Jan. 10, when Maduro was sworn in for a second term following a vote boycotted by the opposition.

Tensions escalated when Guaido, who heads Venezuela’s National Assembly, declared himself acting president on Jan. 23, a move which was supported by the U.S. and many European and Latin American countries.

It is unclear how widespread the military defections seen on Tuesday have become amid economic and humanitarian crises in the Latin American nation.

But National Security Advisor John Bolton called on Venezuela's armed forces to "protect the Constitution and the Venezuelan people."

In a message to Venezuelan Defense Minister Vladimir Padrino Lopez posted on Twitter, Bolton said the Venezuelan military "should stand by the National Assembly and the legitimate institutions against the usurpation of democracy."

Venezuela has been in the throes of humanitarian and economic crises amid the political deadlock between Guaido and Maduro as Washington has ramped up diplomatic and economic pressure on the Venezuelan president, including sanctioning his state-run oil company, in a bid to get him to relinquish power. 

The political stalemate comes as Venezuela grapples with an economy that has been torn asunder by the global decline in the price of oil -- Venezuela's chief export.

The severe economic crisis has led to acute shortages of goods and medicine, and has repeatedly resulted in widespread power outages.