The experts had warned for years: Cuba’s power grid was on the verge of collapse, relying on plants nearly a half-century old and importing fuel that the cash strapped Communist government could barely afford.

On Friday morning their dire predictions came true, as the entire island plunged into the most prolonged blackout it has suffered in the three decades since its former benefactor and steady fuel supplier, the Soviet Union, collapsed.

Cuban energy officials managed to briefly get power back up to some parts of the island on Friday night. But early Saturday the state’s utility company reported another “total disconnection” of the system, the second in less than 24 hours.

Government officials tried to reassure the public that power would be broadly restored over the weekend, but acknowledged they could not be sure.

“We are estimating there should be important progress today,” Lazaro Guerra, the electricity director for the Ministry of Energy and Mines, said in an interview on state television.

“But I cannot assure you that we will be able to have the system fully connected today,” he added.