SAN JUAN, Puerto Rico — A blackout hit nearly all of Puerto Rico early Tuesday as the U.S. territory prepared to celebrate New Year’s, leaving more than 1.3 million clients in the dark. Officials said it could take up to two days to restore power.

The outage hit at dawn, plunging the island into an eerie silence as electrical appliances and air conditioners shut down before those who could afford generators turned them on.

Nearly 90% of 1.47 million clients across Puerto Rico were left in the dark, according to Luma Energy, a private company that oversees electricity transmission and distribution.

Luma said in a statement that it appears the outage was caused by a failure of an underground power line, saying it is restoring power “in the quickest and safest way possible.”

The blackout fanned simmering anger against Luma and Genera PR, which oversees the generation of power in Puerto Rico, as a growing number of people call for their ouster.

Gov.-elect Jenniffer González Colón, who is set to be sworn in Thursday, has called for the creation of an “energy czar” to review potential Luma contractual breaches while another operator is found.

“We can’t keep relying on an energy system that fails our people,” she wrote on X, adding that stabilizing Puerto Rico’s energy grid would be her top priority.

Meanwhile, Gov. Pedro Pierluisi said he was in touch with Luma and Genera PR, adding on X that “we are demanding answers and solutions.”

The outage forced businesses, parks and several malls to close, and the government announced limited schedules for some of its agencies. Workers checked on hundreds of bedridden patients.

Other Puerto Ricans began to plan ahead.

“I’ll go to my balcony. That’s where I’ll sleep,” Raúl Pacheco said with a shrug, as the 63-year-old man with diabetes sat on a walker nursing an injured foot.

Julio Córdova, a municipal worker, said he got dressed by the light of his cellphone and planned to buy candles.

While blackouts are rare in Puerto Rico, the island struggles with chronic power outages blamed on a crumbling power grid that was razed by Hurricane Maria, a Category 4 storm, in September 2017.

The system, however, was already in decline after years of lack of maintenance.

Only recently did crews start making permanent repairs to Puerto Rico’s power grid following Hurricane Maria. The island continues to depend on generators provided by the U.S. Federal Emergency Management Agency to help stabilize the grid.