In a statement, the prosecutor’s office said it has opened the inquiry because Machado’s support for tougher US measures constitutes “treason to the homeland, according to article 128 of the penal code, (and) conspiracy with foreign countries.”

The office said it is “fighting against any person, group, or national or international entity that threatens the stability of the country.”

On Monday, the US House of Representatives passed the Bolivar Act, a bipartisan bill which bars US federal agencies from conducting business with the Maduro regime or its associates. It still needs passage by the Senate and President Joe Biden’s signature for it to become law.

Caracas reacted angrily to the House action, saying the bill would violate the UN Charter.

During Donald Trump’s first term as US president, from 2017 to 2021, he imposed a policy of maximum pressure – including tightening financial sanctions and instituting an oil embargo – in an unsuccessful effort to oust Maduro from power.

Maduro claimed victory in the July election and defied domestic and international calls to release detailed polling numbers to back up the assertion.

The opposition claimed that its candidate Edmundo Gonzalez Urrutia, who had been swiftly picked to run in Machado’s place after she was declared ineligible, won with over 67% of the vote.

Amid an outcry at home and abroad, the former bus driver Maduro, handpicked by the late Hugo Chavez, is now serving his third term in the oil-rich country whose economy is in shambles, as Venezuelans endure acute shortages of food, medicine and other basic goods.

Since the election, Gonzalez Urrutia has fled to Spain due to an outstanding arrest warrant, while Machado has gone into hiding.

Washington has not recognised Maduro’s victory and this week, for the first time, said it recognises Gonzalez Urrutia as Venezuela’s president-elect.