Emperatriz Villamizar, holds her neighbour's medicine after she offered to keep them in her freezer during the ongoing blackout in Caracas, Venezuela. Picture: Reuters/Carlos Jasso

Caracas, Venezuela - Opposition lawmakers and aid groups warned Sunday that an unprecedented nationwide blackout in Venezuela was causing a rising number of deaths, as citizens struggled for a fourth day to find food and water and hospitals were paralysed.

"What Venezuelans are living today looks like a science fiction movie," said Juan Guaido, the opposition leader who is spearheading a US-backed campaign to oust President Nicolas Maduro.

At a news conference Sunday, Guaido said at least 17 deaths had occurred at hospitals as a result of the outages. Fifteen of them were in the eastern city of Maturin, he said. Meanwhile, a medical aid group, Codevida, said it had reports of 15 people who had died due to kidney failure linked to the lack of power.

It was not possible to independently confirm the reports. The Venezuelan government has released little information on the blackout, blaming it on sabotage by US authorities. Trump administration officials have denied the accusation and attributed the power outages to years of underinvestment and poor maintenance. While power was restored to some areas on Sunday, it was often fickle, failing hours later.

The lack of power has left hospitals depending on generators - if they have them - and has also shut the Caracas metro and virtually halted public transportation. That means many medical personnel can't get to their jobs.

On Sunday afternoon, a weeping 24-year-old woman sat in a chair outside the hospital at the Central University of Venezuela. "My baby just died," she said softly. "There was no pediatric surgeon."

The mother, Alexandra Amundaray, a parking-lot attendant, said her 5-month-old son, Emanuel, had been suffering from dehydration in recent days. On Sunday morning, when he awoke, he was pale and cold, she said. She managed to get one of the few functioning ambulances in the city to rush him to the hospital, where he was treated at the emergency room for a blocked intestine, she said. "They went looking for a pediatric surgeon," she said. "And then he died."

The director of the hospital, Earle Siso, said in an interview that no patients had died due to the power outage; a generator was providing electricity for emergency cases. He denied that there was a shortage of medical personnel. "Our biggest problem is the international blockade that's been in effect since the era of President Obama," he said.

But, shortly before talking to a reporter, he was surrounded by doctors and nurses complaining loudly that their colleagues hadn't reported for work.

A woman waiting outside the emergency room for a doctor to see her 6-month-old daughter, who was suffering from a bacterial infection, said she had been told only one doctor was working Sunday in the pediatric ward. The woman spoke on the condition of anonymity, saying she feared government retaliation.

Most of the hospital's corridors were dark Sunday, and there was no running water at the facility. Elias Urbaez, a cardiology resident, said that Sunday was his day off but that he had decided not to return home. He relies on public transportation, and he was worried that he wouldn't be able to get back for his shift on Monday.

Urbaez was dressed in the same plaid shirt and lavender tie he had worn to work on Friday, when he got a ride from a neighbour. The doctor had been washing in a basin of water, "but then the water ran out," he said. In the evenings, he wrote reports by the light of his cellphone.

What would happen if the diesel to operate the generator gave out? "All the doctors are obviously afraid of this," he said.

Maduro tweeted on Sunday that the electrical system "has been the subject of multiple cybernetic attacks that forced its collapse and have hurt the efforts to reconnect it nationally. Nonetheless, we are making great efforts so that, in the next few hours, we will restore power in a stable, definitive form," he said.

But few Venezuelans seemed optimistic that the government would succeed in reviving the electrical grid. Guaido - who has been recognised as interim president by the United States and more than 50 other countries - called for new protests on Monday in response to the blackout.

Power returned in some Caracas neighbourhoods Sunday. In Guarenas, a working-class suburb where residents infuriated by the blackout burned tires and trash on Saturday, electrical service returned early Sunday morning, but electricity failed several hours later. Long lines formed outside bakeries, supermarkets and gas stations that had power.

Oscar Hernandez, 40, was buying candles Sunday at a supermarket in East Caracas. "I'm preparing for Armageddon," said the engineer, who said his family had used up its supply during the blackout. "The government is too incompetent to fix it in the short term."

Victoria Daboin, 27, went to the butcher last week and bought nine chickens, 16 chicken breasts and beef - a major shopping trip in a country suffering from a severe economic crisis. But on Sunday, after 72 hours without electricity, she had to empty her refrigerator because the meat risked spoilage.

"I'm desperate," said Daboin, a municipal worker.

Alicia Medina, 63, said she had been looking for ice all day to try to preserve the food she has at home. "I went to 10 places and nothing" she said, outside a grocery store in East Caracas.

Meanwhile, cellphone service remained spotty in much of the country. On Sunday, about 20 cars had parked on the side of a major Caracas highway. Why? "I know I look like a crazy lady," said Carolina Pardo, a 45-year-old trainer at a gym. "But this is the only place I can get a signal in the entire city, and I need to communicate with my mom, who lives abroad."

The Washington Post