“Stop. Stop, Trump! Hold it right there! You are making mistakes that will leave your hands covered in blood and you will leave the presidency stained with blood,” Maduro warned during a combative interview with the Spanish journalist Jordi Évole. “Why would you want a repeat of Vietnam?”

He also rejected European calls for elections, saying: “We don’t accept ultimatums from anyone. I refuse to call for elections now – there will be elections in 2024. We don’t care what Europe says.”

He added: “You can’t base international politics on ultimatums. That’s the stuff of the empire, of colonial times.”

Tens of thousands of Venezuelan protesters streamed through the capital, Caracas, on Saturday to demand the exit of a president who has led the oil-rich South American nation into economic collapse and humanitarian crisis.

Gisela Torres, a 40-year-old demonstrator, said Maduro had done nothing but “damage and destroy” Venezuela and her message to him was: “Be sensible and understand that you must go.”

But in his television interview Maduro – who came to power after the 2013 death of his political mentor, Hugo Chávez – signalled that he had no plans to go anywhere.

“If the north American empire attacks us, we will have to defend ourselves … We aren’t going to hand Venezuela over,” Maduro said.

The UN estimates that more than 3 million Venezuelans have fled overseas in recent years to escape hyperinflation, shortages of food, medicine and healthcare and chronic insecurity. That number is expected to rise to more than 5 million this year.

But Maduro denied that his country was suffering from a humanitarian emergency and claimed no more than 800,000 people had fled.

“Venezuela does not have a humanitarian crisis,” he said. “Venezuela has a political crisis. Venezuela has an economic crisis … Many people have been tricked into leaving.”

Asked if the challenge to his rule from the opposition leader, Juan Guaidó, and his international allies including the US, meant he was now “against the ropes”, Maduro admitted he was facing a “tough” fight against powerful opponents.

“They use sledgehammers instead of boxing gloves,” Maduro said of the US, which he claimed was seeking to topple him to seize Venezuela’s oil.

“But it’s like David against Goliath,” Maduro went on. “We have our secrets too – and we have our sling. David’s sling is in our hands.”

Maduro also sent a message to his opposition challenger Guaidó, who declared himself Venezuela’s legitimate interim president on 23 January, sparking what many believe could be a final showdown between the two sides.

“Think carefully about what you are doing,” he said, urging Guaidó “to abandon his coup-mongering strategy”.

Asked if he feared that Venezuela could be plunged into war by the crisis, Maduro said: “Everything depends on the extent of the madness and aggression of the northern empire and its western allies. It’s not up to us … We are getting ready to defend our right to peace.”

Speaking to CBS on Sunday, Trump said he had rejected talks with Maduro “because so many really horrible things have been happening in Venezuela”. Asked if military action was possible, he replied: “Well I don’t want to say that. But certainly it’s something that’s on the – it’s an option.”

With the crisis escalating, Maduro has been making near-daily visits to military units in an apparent attempt to project might.

During a visit to a navy base in Aragua state on Sunday he tried to fire up troops by citing Hamlet: “‘To be or not to be?’ the great Shakespeare, used to say. ‘To be or not to be?’

“Should we be a fatherland or a colony? Should we be Venezuela or be nothing? Should we be a united people and armed forces or should we be disintegration?”

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