Venezuela's President Nicolas Maduro says the country's complete electrical failure has been caused by "an international cyber-attack" but that his administration has "defeated their coup".
Power and communication outages continue to hit Venezuela on Sunday, intensifying the hardship of a country paralysed by economic and political crises.
The blackout heightened tensions between the opposition and government loyalists, who accuse each other of being responsible for the collapse of the power grid.
"I will tell this for the first time," Maduro told the hushed crowd in Caracas on Saturday. "We are in the process of investigation and correcting it all because there are many infiltrators attacking the electrical company from within."
Maduro stated that Venezuela had been hit yet again by another "cyber-attack" at noon on Saturday.
'Permanent state of alert'
Speaking to Al Jazeera from the Perez Carreno flagship hospital in Caracas, Lorelei Gorrin, an emergency surgeon, said she had just completed one of the toughest shifts of her life.
"I didn't stop receiving patients. We could only help those who had life-threatening issues," said Gorrin.
"The generator worked, but I was worried it would suddenly stop working. We don't know when we're going to lose power again, or how we're going to deal with that. If we had to resort to manual respiratory aid devices, we would not have enough to help all those that need them.
"We're in a permanent state of alert, which is mentally and emotionally draining," she said.
Across Venezuela, millions of people are affected by the continued blackout.
Valeria Castillo, a 43-year-old actress, told Al Jazeera she briefly "escaped" her home where she takes care of her ailing parents to attend an opposition rally in the capital.
"The entire floor of the house is full of candle wax. My father is very old and sometimes soils himself and washing him has been a real pain with no power and no water as the pump does not work," said Castillo.
Support for Maduro
Still, many Venezuelans continue to support Maduro in his ongoing fight against what he calls US imperialism.
On Saturday, thousands of demonstrators at a pro-Maduro rally danced and waved flags on what organisers labelled a "day of anti-imperialism", in a show of defiance towards the US, which has imposed oil sanctions on Venezuela in an attempt to overthrow the president.
Many showed up wearing red caps and shirts in support of the self-proclaimed "socialist revolution" of leader Hugo Chavez, who died six years ago and was succeeded by his protege, Maduro.
Lidia Calderon, 37, joined the rally saying she relies on Maduro to fix the situation.
"He does what he can to maintain the peace. And it is very clear that the electricity [situation] is a war against the people," said Calderon.
Maduro's government has not moved directly against opposition leader Juan Guaido since he returned to Venezuela from a Latin American tour on Monday.
But on Saturday, Maduro stepped up verbal attacks on Guaido, calling him "a clown and puppet" in a speech to his supporters outside Miraflores, the presidential palace.
He scoffed at Guaido's claim in late January to be interim president of Venezuela, a declaration supported by the US and about 50 other countries.
"We have defeated their coup," said Maduro. "They tried illegitimately to turn into a president a person in a public square and now, today, it is obvious to the world he is not a president, not anything. A clown and a puppet is what that man [Guaido] is. Delinquent citizen."
Maduro also accused Guaido and his US allies of sabotaging Venezuela's Guri Dam, one of the world's largest hydroelectric stations and the cornerstone of Venezuela's electrical grid.
He said authorities had restored 70 percent of power in Venezuela since a nationwide outage hit late Thursday, but progress was lost on Saturday when "infiltrators" allegedly struck again.
The Venezuelan opposition and US officials say Maduro's attempts to pin blame on his political adversaries is absurd, and that government corruption and mismanagement over many years caused the blackout and wider deterioration of the economy.
In another blow to Venezuela's infrastructure, an explosion occurred at a power station in the country's Bolivar state on Saturday, according to local media.
Netblocks, a non-government group based in Europe that monitors internet censorship, said on Saturday that the second outage had knocked out almost all of Venezuela's telecommunications infrastructure.
Additional reporting by Alicia Hernandez in Caracas