A "terrorist attack" ruptured storage tanks at a heavy oil processing plant in eastern Venezuela, Oil Minister Manuel Quevedo said Thursday, blaming the United States and opposition chief Juan Guaido.

No casualties were reported in the incident that occurred late Wednesday at the Petro San Felix facility located on the outskirts of the Venezuelan city of Barcelona in which three tanks caught fire.

Quevedo blamed Guaido, the head of Venezuela's opposition-ruled legislature and self-proclaimed interim president backed by 50 countries, accusing him of collusion with the United States.

"There was a terrorist act that we denounce at an international level," Quevedo told state television network VTV.

He singled out a U.S. senator, Marco Rubio, whom Caracas considers to be a leading politician in the U.S. policies against Maduro's government.

On Twitter, the minister said Rubio "ordered more violence in Venezuela." Guaido and the opposition, he said, were "intensifying terrorist incursions" against the state-owned oil company PDVSA to impact Venezuela's vital crude exports.

"Traitors!" he wrote, adding "the United States has decided to rob Venezuela of its oil resources... (and) wants blood to flow."

Oil exports account for 90 percent of Venezuela's export revenues. Production has long slid, crimped by years of underinvestment and mismanagement. Stepped-up US sanctions have further trimmed exports.

An unprecedented nationwide blackout that lasted nearly a week dealt further damage, affecting most of the one million barrels of oil a day Venezuela still manages to produce, according to the economic analysis firm Ecoanalitica.