Because Maduro has used the military to torture, beat, and kill peaceful dissidents - and was "re-elected" in a vote worldwide observers consider fraudulent - Guaidó invoked constitutional Articles 333 and 350 to take over, with a mandate to hold free and fair elections as soon as possible. He huddled with military troops early Wednesday and has overseen military exercises in recent days while seeking to consolidate support from the armed forces. The government has also responded to his challenge by cracking down on rebellious neighbourhoods, trying to preserve an autocratic, socialist-style system increasingly imperilled by deep unpopularity and foreign pressure.
U.S. military invention is seen in Washington as highly unlikely, but President Donald Trump has repeatedly said "all options are on the table".
Embattled Venezuelan leader Nicolás Maduro has posted a video in Spanish to social media, warning that there would be a new "Vietnam" in Venezuela if the United States doesn't change course. He always relished his role as a bomb thrower during his career in the State Department and then as US ambassador to the United Nations.
Maduro told RIA Novosti that he is "willing to sit down for talks with the opposition for the sake of Venezuela's peace and its future". He also accused Trump of ordering a hit on him from Colombia but offered no proof. US National security adviser John Bolton said that any threat on Juan Guaido or on a USA diplomat, would result in a "forceful reaction".
Earlier in the day, Venezuela's Attorney General Tarek Saab asked the court to launch a criminal probe against Guaido.
Mr Guaido said he did not underestimate the threat of imprisonment but did not believe it was "anything new".
Venezuela's opposition plans protests Wednesday to urge the military, the lynchpin of Maduro's beleaguered regime, to dump him in favor of self-declared interim leader Juan Guaido.
"I am carrying out my duties as commander-in-chief according to the Constitution consolidating the national Bolivarian armed forces", he said.
Venezuela was plunged into political turmoil last week after the United States recognised Guaido, 35, as acting president, while Russian Federation has continued to back Maduro.More news: Zuckerberg plans to merge Facebook, WhatsApp, Instagram
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The U.N. human rights office says security forces in Venezuela detained almost 700 people in just one day of anti-government protests last week and that more than 40 people were killed. The Department of the Treasury imposed sanctions this week on Petróleos de Venezuela (PDVSA), the state-run oil company, which actually bans Americans from buying Venezuelan oil.
Maduro has blamed his country's woes on the United States, which he accuses of working with the opposition to topple the government.
"Even though even our directors say it is not necessary, we know what it is like to see patients die due to lack of supplies", she was quoted as saying.
Support for dueling presidents in Venezuela has broken along traditional lines. The opposition argues Maduro's re-election last May was a sham.
"The transition will require support from key military contingents".
In a tweet on Wednesday, Trump warned USA citizens against traveling to Venezuela, given the unrest.
Venezuela - which has the world's largest proven oil reserves - has suffered an economic meltdown under Maduro's leadership, marked by hyperinflation and shortages of basic necessities such as food and medicine.
The military high command remains loyal to Maduro but Guaido has tried to convince the rank and file to switch sides. China, Cuba, Bolivia and Turkey also back him.