The blackout affected 23 of the country's 24 states on Thursday evening after an “attack” on the Guri Dam, a large hydroelectric facility in east Venezuela, according to the minister of electrical power, Luis Motta Domínguez, Presstv Reported.
The power failure stopped subway service in the capital Caracas and caused many problems around the country.
"The electric energy war declared and directed by the US imperialists against our people will be destroyed,” Motta wrote in a Twitter post on Thursday. “Nothing and nobody will win over” the people of Venezuela, he added.
Information Minister Jorge Rodríguez also accused right-wing “criminals” of committing “sabotage” to the dam’s system of generation and distribution.
"They sabotaged the central generator... it's part of the electric war against the state,” the electric company CORPOELEC said, adding it was working to re-establish the service.
US-backed opposition figure Juan Guaido, who declared himself president, took advantage of the power outage, accusing Maduro’s government of “inefficiency”.
“Venezuela is clear that the light will return with the end of usurpation,” he said.
US Secretary of State Mike Pompeo also accused Maduro of “incompetence," saying the responsibility rested with his government.
The US, which has long been pushing to oust the elected government of Maduro, has threatened several times to take military action to topple him.
Washington has also recognized Guaido as the interim president and imposed economic sanctions on the country. The US recently confiscated Venezuela's state oil assets based in the US to channel them to the opposition.
On Thursday, Trump’s special representative for Venezuela threatened to “expand the net” of sanctions on the country.
“There will be more sanctions on financial institutions that are carrying out the orders of the Maduro regime,” said Elliott Abrams.
China's stern warning
China's top diplomat on Friday warned against interfering in Venezuela and imposing sanctions, saying saying the sovereignty and independence of Latin American countries should be respected.
"The internal affairs of every country should be decided by their own people. External interference and sanctions will only exacerbate the tension situation, and allow the law of the jungle to once again run amok," State Councillor Wang Yi said.
"There's already enough of such lessons from history, and the same old disastrous road should not be followed," he said at his annual news conference on the sidelines of China's parliament meeting.
The US is unhappy about China's warming relations with Latin American countries. Last month, US national security adviser John Bolton called on El Salvador to cooperate on what he called the "predatory" expansion of China.