The Trump administration on Monday imposed sweeping sanctions on Venezuelan state-owned oil firm PDVSA, the toughest USA financial challenge yet to the country's embattled socialist president, Nicolas Maduro.
Any actions taken against U.S. diplomats, Guaido or the National Assembly he presides over would be considered a "grave assault" that "will be met with a significant response", U.S. National Security Adviser John Bolton said.
Details of the U.S. plan comes as tensions in Venezuela threaten to boil over after opposition leader Guaido called for a strike on Wednesday followed by a large scale protest on Saturday against Maduro's government.
Guaido, 35, heads the opposition-controlled National Assembly and declared himself acting president in Caracas on Wednesday during an anti-government rally by tens of thousands of people. "They are attacking us and they think Venezuela is their back garden", Maduro said.
Bolton joined Treasury Secretary Steven Mnuchin in addressing new steps against the government of Venezuelan President Nicolás Maduro, who the US has deemed "illegitimate" in the face of a political challenge by National Assembly head Juan Guaidó.
The Florida Republican represents a large Venezuela expatriate community and is a vocal opponent of the Maduro regime, which the USA declared illegitimate last week.
"The United States has a long history of inappropriately intervening in Latin American countries", said the senator.
Most of the Lima Group has urged Venezuelan President Nicolas Maduro to step down as his country sinks further into economic and political crisis, suffering shortages of food and medicine, and skyrocketing inflation.
The small number of USA diplomats in Venezuela, he said, "will remain and comfortably continue their lives with the protection we will provide for them".
She also noted that the United Kingdom, France, Germany and Spain also stated over the weekend that they, too, recognize Guaido and would continue to do so unless free and democratic elections are held in the country by Saturday.
U.S. President Donald Trump assailed Maduro in a letter to Congress explaining an executive order he issued sanctioning PDVSA and Venezuela's central bank.
Mr Guaido claims he is entitled to the presidency on the basis that President Nicolas Maduro's reelection to a second six-year term was fraudulent.
On Saturday, Venezuela's military attaché in Washington, Col. José Luis Silva Silva said he stands with Guaido.
Soldiers are seen at a military headquarter as opposition supporters (not pictured) give out copies of amnesty measures to anyone in the military who disavows President Nicolas Maduro, in Caracas, Venezuela, Jan. 27, 2019.
"Where do you get that you have the power to establish a deadline or an ultimatum to a sovereign people?" said Venezuelan Foreign Minister Jorge Arreaza.
Both Russia and China are major creditors of Venezuela.
"It is most important now that Venezuelans themselves should settle all differences that can be between them in the framework of the constitution and the only help that all of us can offer is not to meddle in the situation like certain countries are doing directly", Peskov stressed.