Venezuelan officials described the threat as "an act of craziness"
US President Donald Trump has threatened Venezuela with a possible "military option".
Venezuela has become more unstable since its president Nicolas Maduro won a controversial election giving him new constitutional powers to bring forth what Washington describes as his "dictatorship".
More than 120 people have been killed and thousands of people, including opposition activists, have been arrested during the past four months.
Mr Trump described the situation in Venezuela as a "very dangerous mess".
He said: "We have troops all over the world in places that are very far away.
"Venezuela is not very far away and the people are suffering and they're dying.
"We have many options for Venezuela, including a possible military option if necessary."
When asked if the US would lead any operation in Venezuela, Mr Trump said: "We don't talk about it but a military operation - a military option - is certainly something that we could pursue."
Venezuela's defence minister Vladimir Padrino told state television on Friday that Mr Trump's threat was "an act of craziness, an act of supreme extremism."
"With this extremist elite that's in charge in the US, who knows what will happen to the world?"
The country's communications minister Ernesto Villegas, meanwhile, called the threat "an unprecedented threat to national sovereignty".
Although Mr Maduro has requested a phone conversation with Mr Trump, the White House said the US president would speak with his Venezuelan counterpart "when democracy is restored".
A spokesman for the US Department of Defense, Eric Pahon, would not comment on Mr Trump's threat of military action but did say that, "as of right now, the Pentagon has received no orders" regarding Venezuela.
Some officials in Venezuela have long accused the US of planning an invasion and earlier this year, a former military general told Reuters news agency that anti-aircraft missiles were on the country's coast as a precaution.