"Food stocks are starting to rot. There's no water. The transport virtually doesn't work. There's no means of communication. I don't know how my family is doing. Insecurity is growing," said Nestor Carreno, who was forced to shutter his pizzeria in a formerly upscale district of Caracas.

A cacophony of saucepans being banged out of windows and car horns in the street has been heard since the start of the vast outage -- the second this month.

Memories of the first, which started March 7 and lasted a week, forcing citizens to seek water from rivers and sewage outflows as pumps came to a halt, fed the anguish. Many residents stocked up on food and water.

In several neighborhoods, the power flickered back at times, only to disappear shortly afterwards.

Although the country has the biggest proven reserves of oil in the world, it has been unable to prevent the power cuts. Or to repair them swiftly.

The government of President Nicolas Maduro, which blamed the blackouts on US "cybernetic" attacks and opposition "sabotage," decreed the closure of public offices and schools until Wednesday night.

The outage was affecting 21 of Venezuela's 23 states, according to users on social media. The government has given no official information on its scale.

Juan Guaido, the opposition leader whom the US and many of its allies recognize as the country's interim president over "illegitimate dictator" Maduro, called for a national protest on Saturday over "the lack of public services."

"The light has gone, we can't remain passive actors," he told supporters.

He has rejected the government allegations that the opposition was behind the latest blackout as "lies."

"We don't know how long this situation will go on for," said Lucia Antiqueira, outside the fruit-and-vegetable shop where she worked.

"As it drags on, things get more complicated for electronic payments. There are few places that have a generator and people are getting more and more anxious," she said.

Experts calculate the lack of power was costing Venezuela's economy $200 million per day.

As with the previous blackout, the consequences for Venezuelan hospitals was dramatic.

Outside a children's hospital in Caracas, Junior Veliz was mourning the loss of his newborn baby, who was in intensive care and died when the power went out.

"The electricity went out. She died of a heart attack because of the blackout... the hospital didn't have a generator," he said.

Power cuts have become frequent in Venezuela over the past few years, underlining the long slide into crisis the country, once South America's wealthiest, has experienced.

Maduro, in a tweeted statement, said Tuesday a "large-scale fire" set by "terrorists" disrupted the power supply from the country's main electricity generation plant, the Guri hydroelectric dam on the Orinoco river in the south that supplies 80 percent of Venezuelans.

Guaido rejected that version.

"They are not giving any sensible, credible explanation," he told lawmakers in the opposition-run congress on Tuesday. "When it's not a 'cyberattack' or an 'electromagnetic pulse' it's 'sabotage,' despite them militarizing more and more the electricity stations."

Outside of the anxiety and political exchanges over the blackout, the presence of Russian troops in Venezuela has made the climate more febrile.

"It seems (Maduro's government) doesn't trust its own troops, because it is importing others... once again violating the constitution," Guaido said.

Under Venezuela's constitution, any foreign military mission in the country needs to be approved by the congress.

Russia, Maduro's main ally and one of its biggest creditors along with China, on the weekend sent 100 troops and 35 tons of military equipment aboard two flights to Caracas.

Moscow said it was done in "full respect for (Venezuela's) legal norms" and to head off what it described as a US-organized "coup."