Workers on the stairs of an office building in Caracas amid the blackout.

CARACAS, Venezuela — The lights have gone out across much of Venezuela, snarling traffic in the capital and reviving fears of the blackouts that plunged the country into chaos a few months ago.

The power in the capital went out after 4 p.m. and immediately backed up traffic as stop lights and the subway stopped working during rush hour.

“This is horrible, a disaster,” Reni Blanco, a 48-year-old teacher, said as she joined a crush of people who flooded into the streets of the capital trying to make it home before nightfall.

Authorities have yet to comment and it was unclear the scale of the outage.

But there were reports on social media that 19 of 24 Venezuelan states were also affected. Netblocks, a group monitoring internet activity, said network data showed most of Venezuela was knocked offline with national connectivity at just 6% after the latest cuts. The normally nonstop state TV channel, a key way for the government to keep people informed, was also off the air, leaving frustrated Venezuelans to wonder how long they would be left in the dark.

Blackouts roiled the country in March, leaving much of the capital without power and water for almost a week. President Nicolás Maduro blamed the outage on a US-sponsored “electromagnetic attack” against the nation’s biggest hydroelectric dam. More recently, as power service in the politically crucial capital has improved amid widespread rationing in the interior, officials have even taken to downplaying the outages as similar to recent ones in Argentina and even one that knocked off the power for several thousand residents of Manhattan for a few hours amid the summer heat.

But his opponents said the outage laid bare years of underinvestment in the nation’s grid by corrupt officials who mismanaged an oil bonanza in the nation sitting atop the world’s largest crude reserves.

“They tried to hide the tragedy by rationing supplies across the country, but their failure is evident: they destroyed the system and they don’t have answers,” opposition leader Juan Guaidó said on Twitter.

Guaidó, whom the US and more than 50 other nations recognize as Venezuela’s rightful leader, reiterated an earlier call for nationwide protests on Tuesday.

“We Venezuelans won’t grow accustomed to this,” he said.

Much of the government’s focus since the March blackouts has been on repairing transmission lines near the Guri Dam, which provides about 80% of Venezuela’s electricity.

José Aguilar, a power expert who lives in the US but hails from Venezuela, said that alternative power plants running on diesel fuel and gas are unable to make up the difference.

“Venezuela simply doesn’t have enough megawatts available,” he said on Twitter. “Any failure shuts down the entire system.”

Despite the risks of another extended collapse, some Venezuelans were taking the blackout in stride.

Cristian Sandoval, a 37-year-old owner of a motorcycle repair business, said he is more prepared for a prolonged outage having equipped his home with a water tanks and a generator for his worship. As Venezuela’s crisis deepens, the sale of electric generators is one of the few growth industries in a country ravaged by six-digit inflation and cratering public services.

“If the blackout continues we’ll have another round of dessert,” he chuckled while sharing a piece of chocolate cake with a friend at a cafeteria growing steadily dark as the night began to fall.

“But it’s very difficult for the people,” he conceded. “This creates a lot of discomfort.”