US National security adviser John Bolton said that any threat on Juan Guaido or on a USA diplomat, would result in a "forceful reaction". Tarek William Saab pointed out that the plea was made in the midst of an ongoing investigation against Guaido to bar him from leaving the country and to freeze his assets.
On one side of the tussle for control of Venezuela - an OPEC member with the world's largest oil reserves but in dire financial straits - Guaido and Western backers led by the United States are insisting on an immediate transition and fresh elections.
Maduro accuses the opposition of staging a coup and says the USA is waging an economic war aimed at removing him from power.
"There is a campaign has been prepared, in order to justify a government-Donald trump prepared, financed and actively supported the coup in Venezuela", said Maduro.
Last week, the United States recognized Guaidó as the rightful interim president and leader of the South American country, and 26 other countries soon followed.
"Don't shoot people who are making demands also for your family", Guaido said in a message to the military delivered from the central university in Caracas.
Perhaps most brazenly, Bolton appeared in an interview on Fox Business and disclosed that the US government was in talks with American corporations on how to capitalize on Venezuela's oil reserves, which are proven to be the world's largest.
The 35-year-old National Assembly president, an engineer by training, is attempting to force the 56-year-old Maduro from power so he can set up a transitional government and hold new presidential elections.
The United States has refused to rule out military intervention in Venezuela and Donald Trump's National Security Adviser John Bolton was even photographed on Monday at the White House holding a notepad with the scrawled line: "5,000 troops to Colombia".
But for now, the military high command remains loyal to Maduro.More news: Steph Curry: Warriors Can Still Get Better
More news: 5 officers wounded in Houston shooting
More news: Brianna Decker to get her National Hockey League skills challenge prize money after all
Venezuela is a rare Moscow ally in Latin America.
On Monday, the USA imposed sanctions on Venezuela's state-owned oil company, Petroleos de Venezuela SA, that could potentially deprive the Maduro government of $11 billion in export revenues over the next year.
Venezuela's President Nicolas Maduro said he was prepared to hold negotiations with the US-backed opposition and added he would support early parliamentary elections, RIA Novosti reported on Wednesday.
"Right now, the U.S. is producing enough and the markets are sufficiently flushed that it may not disrupt" the oil market, he said.
Meanwhile, Russian Deputy Finance Minister Sergei Storchak told Russian state news agencies Tuesday "there will probably be problems" for Venezuela in paying its debts.
Maduro called the sanctions "criminal" and vowed to challenge the U.S.in court.
Maduro had ordered the United States to pull its diplomats by last Saturday.
"Do not travel to Venezuela due to crime, civil unrest, poor health infrastructure, and arbitrary arrest and detention of USA citizens", said the State Department's travel advisory, which was issued as protests continue to sweep Caracas.
Opposition leaders have called for anti-government demonstrations this week.