Caracas: Sporadic looting and spontaneous protests. Desperate patients begging doctors to be kept alive. Residents bracing for wider attacks on markets and restaurants after the sun goes down.

It was the fourth day on Sunday since Venezuela's power system went down, plunging most of the country, including Caracas, the capital, into sporadic darkness and dampening hopes of imminent resolution to a devastating blackout that has brought the country to the verge of social implosion.

"We're going to arrive at a moment when we're going to eat each other," said Zuly González, 40, a resident of Caracas' Chacao neighbourhood.

The blackout is the latest calamity to befall a country in seemingly perpetual crisis. Venezuela has been devastated for years by hyperinflation and a failing economy that has led millions to flee. But the country has been further torn since January, when opposition leaders refused to acknowledge as legitimate the re-election of President Nicolas Maduro.