"Donald Trump has without doubt given an order to kill me and has told the government of Colombia and the Colombian mafia to kill me," the embattled South American leader said.
The State Department has already warned Americans not to travel to the country.
Venezuelan President Nicolás Maduro refused to submit to what he called "imperialist" international demands for a new election amid his power struggle with opposition leader Juan Guaidó.
President Donald Trump's son Eric Trump told Fox News host Sean Hannity that Democrats would turn America into crisis-hit Venezuela.
"The U.S. government has limited ability to provide emergency services to U.S. citizens" in the country, the advisory warned.
China said, "History has taught us that external interference or sanctions, instead of helping solve problems, can only complicate matters."
"In the face of any aggression, of any nature and intensity, we will defend Venezuela, as it belongs to us," said Defense Minister Vladimir Padrino, who is standing by embattled President Nicolás Maduro.
White House national security adviser John Bolton's legal pad notes appeared to say: "Afghanistan —> welcome the talks. 5,000 troops to Colombia."
White House national security adviser warned of a "significant response" to any harm that came to U.S. citizens at the hands of Venezuela.
Russia and Iran's top diplomats "shared readiness to help facilitate mutual understanding between responsible political forces of Venezuela."
The country's self-declared interim president asked supporters to take to the streets on Wednesday.
The senator said Trump was discussing military options just weeks ago.
Venezuela has reportedly accepted the offer, citing Russia's "great similar experience" in settling world conflicts.
Trump has recognized a Venezuelan opposition leader as head of state, cutting ties with President Maduro in a move Democratic critics described as a coup.
This is the best shot Venezuela had at democracy for a generation—and the U.S. can't afford to sit this one out.
The United States has called on Venezuela's Nicolás Maduro to step down, but Russia is backing him.
"Is it possible Rep. Ocasio-Cortez could be wrong about the demise of the planet in 12 years?" Graham tweeted.
China, Cuba, Iran, Russia, Syria and Turkey were among those to immediately condemn any plans for U.S. intervention in Venezuela.
I had a chance to witness the human stories behind this crisis first-hand. The U.S., governments across South America and international donors must step up to help.
The U.S. and EU are among those backing Juan Guaidó as interim president while urging Nicolás Maduro to step aside as Venezuela's leader.
"We continue to hold the illegitimate Maduro regime directly responsible for any threats it may pose to the safety of the Venezuelan people," Trump warned.
The Trump administration has officially recognized the Venezuelan National Assembly as the legitimate democratic government of the South American country.
"Depending on what happens in the world, who knows if we would not need to discuss that question in the future," Brazilian President Jair Bolsonaro said.