China has rejected US claims that it is partly to blame for the disintegration of Venezuela, accusing Washington of slandering Beijing and “spreading chaos” in Latin America.

During a four-country tour of South America last week, the US secretary of state, Mike Pompeo, pilloried Beijing for continuing to back Venezuela’s embattled president, Nicolás Maduro.

“China’s bankrolling of the Maduro regime helped precipitate and prolong the crisis in that country,” said Pompeo, who described Maduro as “a power-hungry tyrant who has brought ruin to his country and to his people”.

“I think there’s a lesson … to be learned for all of us: China and others are being hypocritical calling for non-intervention in Venezuela’s affairs. Their own financial interventions have helped destroy that country,” Pompeo added, claiming Chinese money had been used to pay off Maduro’s cronies, crush pro-democracy activists and fund ineffective social programs.

China, which is Venezuela’s biggest foreign creditor and is estimated to have provided up to $62bn (£47bn) of loans since 2007, reacted angrily.

The foreign ministry spokesman, Lu Kang, slammed Pompeo’s “groundless allegations” and “attempts to slander China and sow discord between China and Latin American countries”.

“The US has long been treating Latin America as its backyard, where it would resort to willful use of pressure, threat or even subversion. People can tell right from wrong. I am sure Latin American countries are fully capable of telling a true friend from a false one who is ignoring rules and spreading chaos,” Lu told a press conference in Beijing on Monday, according to an official transcript.

China’s ambassador to Chile, Xu Bu, was even less diplomatic. “Mr Pompeo has lost his mind,” he told the Chilean newspaper La Tercera.

As Pompeo concluded his tour of Chile, Colombia, Paraguay and Peru on Sunday, Juan Guaidó, the US-backed opposition leader currently battling to dislodge Maduro, appealed to China to abandon Hugo Chávez’s authoritarian heir.

Guaidó, who is recognized as Venezuela’s legitimate interim leader by more than 50 governments, said Beijing would find “a willing, open and more reliable partner in Caracas” if it backed him.

Analysts suspect China’s pragmatic Communist party leaders – who engage with governments of all stripes across Latin America – would not mourn Maduro’s downfall.

However, almost three months after Guaidó launched his push to topple Maduro on 23 January, there is no sign of that happening, with Venezuela’s military and world powers such as China, Russia and Turkey continuing to offer support.

Lu, the foreign ministry spokesman, indicated that US “smear” campaigns would not change that.

“A lie will remain a lie, even if repeated a thousand times,” he told reporters. “Monsieur Pompeo might as well take a break.”