The power "came for one moment and went away again", Antonio Belisario, who had been waiting around an hour for petrol, told AFP.
At a competing march organized by the Socialist Party to protest what it calls US imperialism, Maduro blamed the outages on "electromagnetic and cyber attacks directed from overseas by the empire". Marco Rubio- of perpetrating an "electrical war" against his country. A reporter for state television described it as a "national blackout". If you're in your home, stay in your home. "It is not just any blackout", said Luis Martinez, a 53-year-old construction worker walking to work in eastern Caracas.
But as the blackout wore on, patience was running thin. "My bad", posted Rubio on social media. Even state TV - the government's main vehicle for handing down a political line to its followers - went silent.
The power cut has caused phone networks to stop operating, shops to close and flights to be diverted from the main Caracas airport. At the maternity ward at the Avila Clinic in Caracas last night, mothers wept as nurses monitored the vital signs of premature babies in incubators by candlelight.
Marielsi Aray, a patient at the University Hospital suffering from an aggravated infection, died at dawn on Friday after her respirator stopped working, her uncle Jose Lugo said. He rejected the government's assertion of sabotage as false.
"Today we'll show them in the streets", he said.
The United States and about 50 other countries back Guaido's contention that he is the interim president of Venezuela, and that Maduro's re-election a year ago was illegitimate because major opposition leaders were barred from running.
The United States and about 50 other countries support Guaido, 35, who has been unable to wrest power from Maduro.
"There's no water, no light, no food". The move is supported by the USA and about 50 other countries.
Venezuela plunges into darkness amid widespread outage
Maduro's televised speeches have on several occasions been interrupted by power outages, spurring chuckles from opposition critics.
An estimated 2.7 million people have left the country since 2015.
Services slowly resumed in Caracas and in the states of Miranda and Vargas, where the country's global airport and main port are located.
Mr Guaido called on his supporters to keep up the pressure on the Maduro government.
Problems have been exacerbated by hyperinflation the International Monetary Fund says will reach 10 million per cent this year.
State-owned electricity operator Corpoelec blamed the outage on what it called an "attack" on the Guri Dam, one of the world's largest hydroelectric stations and the cornerstone of Venezuela's electrical grid. Rodriguez described it as a "cyber" attack meant to derail the whole system.
Though electricity supply is restored in some parts of Venezuela after the worst blackout in decades, the blame game between the two leaders continues.
"What's the intention?" he said.
Netblocks, a non-government group based in Europe that monitors internet censorship, said Saturday a second outage had knocked out nearly all of Venezuela's telecommunications infrastructure. Maduro accuses Guaido of conspiring with the Trump administration in a campaign to overthrow him. "To submit the Venezuelan people to various days without electricity to attack, to mistreat, so that vital areas would be without power".