Updated

Venezuela's chief prosecutor said Thursday he has launched an investigation into opposition leader Juan Guaido's appointment of a transitional board of directors for the state oil company.

Attorney General Tarek William Saab said the appointments by Guaido and his National Assembly are part of an illegal power grab backed by foreign governments. He also said that ambassadors of Guaido's self-declared interim government are being investigated as part of the probe.

"Clearly, this legislative body through criminal means pretends to seize national powers," Saab said in a news conference broadcast on state TV, calling the move part of a "circus."

Guaido declared last month that he has a constitutional right to presidential power as head of the opposition-controlled National Assembly. He currently has support from the U.S. and about 60 countries which are urging President Nicolas Maduro to step down.

Saab said he's looking into the board members who were designated on Wednesday to oversee PDVSA and its Houston-based subsidiary Citgo. Guaido has also been put under investigation and been forbidden from leaving the country, but has managed to avoid arrest.

The struggle for control of Venezuela could now come to a potentially violent head on Feb. 23, when Guaido said he will try to run caravans of U.S. humanitarian aid across the Colombian border into Venezuela. The United States and other countries will also send supplies through Brazil and the Caribbean island of Curacao.

Maduro has blocked the emergency food and medicine from entering and says that the intervention is part of a U.S. coup attempt.

An oil-rich nation, Venezuela was once among Latin America's wealthiest and politically stable nations. However, oil production has collapsed to one-third of historic output, which critics blame on two decades of socialist rule.

The administration of U.S. President Donald Trump recently lodged sanctions that it says could further cripple the country by cutting off an estimated $11 billion in cash-flow to Maduro's government this year.

On Thursday, the White House said that Trump will travel to Florida International University in Miami to warn of "the dangers of socialism" in a Monday speech in support of Guaido.

Trump is looking to draw a contrast with the policies of progressive Democrats, which he has branded as "socialist" as he gears up for re-election.