According to Maduro, the systems had been almost 70 percent restored when "we received another attack, of a cybernetic nature, at midday... that disturbed the reconnection process and knocked out everything that had been achieved until noon".
The United States and about 50 other nations support Guaido's claim that he is the interim president and that Maduro should resign so elections can be held and the more than 3 million Venezuelans who have fled their troubled country can start to return.
Opposition lawmakers denounced the overnight arrest of three people who were setting up a stage at the opposition rally site.
"All the options are on the table", added the National Assembly president, using a phrase employed by US President Donald Trump, who has consistently refused to rule out a military intervention in Venezuela.
"President @jguaido, (you should) formally request Humanitarian Intervention, applying the concept of R2P, to stop extermination, genocide and destruction of what's left of our country", Ledezma wrote via Twitter.
The demonstrations come after on Thursday a blackout swept Venezuela as national electricity supplier Corpoelec reported a "sabotage" at the major Guri hydroelectric power plant.
"We are talking about 95 per cent of dialysis units, which today likely hit 100 per cent, are paralysed, due to the power outage", Mr Francisco Valencia, director of the Codevida health rights group said, warning that in all, some 10,200 people were at risk.
Earlier, unconfirmed reports suggested that 95 percent of the crisis-stricken country was again without power, after Sidor Substation in Bolivar state had allegedly exploded, spewing clouds of black smoke into the sky.
Jussie Smollett Hate Hoax Causes 'Huge Divide' on 'Empire' Set
Earlier this month, the 36-year-old Empire actor was indicted on 16 felony counts by a grand jury in Chicago. In a statement to ET, Geragos said: "The fact of an indictment was not unexpected".
It was one of the worst and longest blackouts in recent memory in Venezuela and paralysed most of the country.
We discovered that they were carrying out high-tech... attacks against the power systems.
Furthermore, hundreds of passengers were left stranded as flights were cancelled at Caracas' Simón Bolívar International Airport owing to the electricity disruption.
"The problem is food, I'd bought meat and it's going bad".
Shops remained closed in Caracas and elsewhere on Friday due to the massive power outage.
"Last night was insane", José Luis Mesa, a 49-year-old electrician whose infant grandchild was being treated in the emergency room, told The Washington Post.
Witnesses described scenes of chaos at several hospitals as people tried to move sick relatives in the dark to clinics with better emergency power facilities.
These photos capture the mood in Venezuela at night throughout the lengthy blackout.
Critics blame the government for failing to invest in maintaining the electrical grid, although the government often blames external factors when the lights go out.