As the lights suddenly turned off across Havana, residents who were sat outside to get some respite from the summer heat audibly groaned en masse.

Cuba has been suffering rolling power cuts due to aging equipment and a US energy embargo that halted regular deliveries of fuel for power stations.

State-run UNE said there was a “total disconnection” of the national electricity system, plunging the country, including the capital, into abrupt darkness.

This is just the latest in a series of total collapses of the electricity grid.

Just 24 hours ago, the whole west of the country went dark.

The power cuts have made normal life almost impossible, with each outage also meaning that water supplies trickle away and ceiling fans slow to a halt.

It is a growing strain for a society used to adversity but now stuck in a months-long crisis that has no obvious end in sight.

Residents in the worst-affected areas have vented their frustrations by setting piles on trash on fire or banging on pots and pans.

The Ministry of Energy said that protocols to reactivate the grid were underway.

Washington has authorized the arrival of only one Russian tanker — carrying 100,000 tons of crude — which came in March. Those reserves have since been exhausted.

In addition to enacting an oil blockade, the Trump administration has ramped up sanctions against Cuban state-owned businesses, prompting many foreign firms to suspend operations in the country.

The United States has also indicted former president Raul Castro, brother of revolutionary leader Fidel Castro, over the downing of two civilian planes three decades ago.

Talks between Havana and Washington appear to have amounted to little.

Havana has enacted a series of free-market reforms to give the economy a boost.

arb/mjw