Venezuela blames opposition leader Juan Guaido and the US after much of the country plunged into darkness.

Venezuelan President Nicolas Maduro on Thursday blamed “American imperialism” for a prolonged power outage which affected most of the South American country.

The embattled president blamed the blackout on “the electrical war announced and directed by American imperialism against our people”, he said on Twitter.

But US Secretary of State Mike Pompeo denied Washington was behind it. “Power shortages and starvation are the result of the Maduro regime’s incompetence.”

State-owned electricity operator Corpoelec blamed the outage on the act of “sabotage” at the Guri Dam, one of the world’s largest hydroelectric stations and the cornerstone of Venezuela’s electrical grid.

Speaking from the capital Caracas, Al Jazeera’s Teresa Bo described the city as being completely in the dark.

“The government is saying that the opposition and its leader Juan Guaido are behind this attack, as well as the US,” she said, adding that many states remain without electricity.

For his part, Guaido, the self-declared interim leader said early on Friday that all but one of Venezuela’s 23 states had no electricity and that capital Caracas had been without light for “a record” six hours.

“This blackout is evidence of the usurper’s inefficiency,” Guaido said on Twitter, referring to Maduro.

Venezuela’s Communication Minister Jorge Rodriguez told state broadcaster Telesur that some 10 states had been affected by the blackout, which he called “brutal electrical sabotage”, adding that the power was back on in three states and the rest of the country would follow within hours.

“What’s the intention?” he said. “To submit the Venezuelan people to various days without electricity to attack, to mistreat, so that vital areas would be without power.”

Rodriguez also accused US Senator Marco Rubio of being involved in the “sabotage”, claiming that he “predicted” the power outage before it happened.

“My apologies to [the] people of Venezuela,” Rubio responded on Twitter. “I must have pressed the wrong thing on the ‘electronic attack’ app I downloaded from Apple. My bad.”

Maduro has presided over a massive economic crisis since he succeeded Hugo Chavez as president in 2013. The prolonged crisis has seen large numbers of people facing food and medicine shortages forcing millions to leave the country.