"In its role as the only legitimate branch of government duly elected by the Venezuelan people, the National Assembly invoked the country's constitution to declare Nicolas Maduro illegitimate, and the office of the president therefore vacant".
Guaido, who is now the President of the National Assembly, swore an oath and declared himself interim president on Wednesday as thousands took to the streets calling for Maduro to leave office.
In a tit-for-tat diplomatic squabble, Maduro cut formal relations with the United States and gave its ambassador a 72-hour deadline to pack his bags and go.
But Pompeo said the US would instead abide by Guaido's directive that countries retain their diplomatic missions in the South American country.
We encourage other Western Hemisphere governments to recognise National Assembly President Guaido as the Interim President of Venezuela, and we will work constructively with them in support of his efforts to restore constitutional legitimacy.
To ratchet up pressure on Maduro, who began a second term on January 10 following an election previous year widely considered to be a fraud, the United States is seeking to cut off funds for his government, US officials said on Thursday.
The Nepal Communist Party has criticized the U.S. and its allies' intervention in the internal affairs of Venezuela, saying that the act is meant to "increase violence by dividing the people and challenging democracy, sovereignty and peace".
Maduro has presided over Venezuela's spiral into its worst-ever economic crisis, with hyperinflation forecast to reach 10 million per cent this year.
Guaido's political mentor, Leopoldo Lopez, was arrested in 2014, one of dozens of opposition activists and leaders the government jailed for seeking to overthrow Maduro through violent street demonstrations in 2014 and 2017.
Juan Guaido has said he needs the backing of three key groups: The people, the global community and the military.
While Canada and others have supported Guaido, Venezuela's top military brass pledged their support for Maduro on Thursday, delivering vows of loyalty before rows of green-uniformed officers on state television.
Tory MP Simon Clarke told MailOnline: 'There is no end to the excuses Jeremy Corbyn will come up with to avoid condemning a regime that has descended into brutality and left so many of its people in degrading poverty.
The military has remained loyal to Maduro through years of economic crises and anti-government actions, but rogue military elements have launched periodic uprisings and presidential assassination attempts nonetheless.
"Maduro relies on the military, and they rely on him, to enrich themselves and avoid facing trial if the regime ultimately falls", said Salamanca.
Cuba, however, sprang to the defence of its socialist ally, expressing "solidarity" with Maduro while Mexico extended lukewarm support to him.
Russian Federation accused the U.S. on Thursday of trying to usurp power in Venezuela and warned against military intervention, putting it at odds with Washington and the European Union which backed protests against one of Moscow's closest allies.
Why has Donald Trump sided with Juan Guaido?
The constitutionality of Guaido's move is unclear.
The Trump administration could impose sanctions on Venezuelan oil as soon as this week, according to sources.