SAN JUAN, Puerto Rico —

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

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

“It had to be December 31st!” shouted a man who gave his name only as Manuel as he stood outside a grocery store in the capital, San Juan, grumbling about the outage, which coincided with his birthday. “There is no such thing as happiness.”

According to Luma Energy, a private company that oversees electricity transmission and distribution, nearly 90% of the 1.47 million customers across Puerto Rico remained in the dark.

As of Tuesday evening, more than 336,000 customers, including 16 hospitals and the Puerto Rico Water and Sewerage Company, had power restored, Luma said. However, the company’s website listing who remained without power was unavailable.

“We understand the great frustration this outage has caused, especially on a day like today,” Luma said in a statement. “We apologize for disrupting your plans.”

Luma said the power outage was likely caused by the failure of an underground power line. It said it would restore power “in the fastest and safest possible way.” Hugo Sorrentini, a Luma spokesman, told the Associated Press that the incident was under investigation.

Discover Puerto Rico, a nonprofit that promotes the island, warned travelers about the outage on its website and urged cruise passengers to contact tour operators directly to determine if they have generators and are open that day.

Five cruise ships were scheduled to dock in Puerto Rico on Tuesday. While most hotels operated on generators, short-term rentals without generators reported cancellations. The main international airport in San Juan remained open.

The blackout fueled simmering anger against Luma and Genera PR, which oversees electricity production in Puerto Rico, as more people call for their ouster.

Gov.-elect Jenniffer González Colón, who is scheduled to be sworn in on Jan. 2, has called for the creation of an “energy czar” to review possible contract violations by Luma while another operator is found.

“We cannot continue to rely on an energy system that is failing our people,” she wrote on the social media platform X, adding that stabilizing Puerto Rico’s energy grid would be her top priority in office.

Meanwhile, Governor Pedro Pierluisi said he was in contact with Luma and Genera PR, adding on X that “we demand answers and solutions.”

President Joe Biden spoke to Pierluisi on Tuesday evening about the outage and offered federal assistance. Biden also spoke with U.S. Energy Secretary Jennifer Granholm and directed her to offer any assistance needed to expedite the restoration of power to the island.

The outage forced businesses, parks and several malls to close, and the government announced reduced hours for some of its agencies. Workers examined hundreds of bedridden patients and handed out ice to diabetics to keep their insulin cold.

Other Puerto Ricans began planning ahead.

“I’m going to my balcony. I’ll sleep there,” Raúl Pacheco said, shrugging, as the 63-year-old diabetic sat on a walker and tended to an injured foot.

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

“It touches me because I had plans. “It couldn’t have been yesterday or tomorrow?” he said, shaking his head as he raked leaves.

While island-wide power outages are rare in Puerto Rico, the U.S. territory struggles with chronic blackouts stemming from a crumbling power grid that was leveled in September 2017 by Hurricane Maria, a Category 4 storm.

However, the system was already in decline after years of lack of maintenance and investment.

Most recently, crews began making permanent repairs to Puerto Rico’s power grid following Hurricane Maria. To stabilize the grid, the island continues to rely on generators provided by the U.S. Federal Emergency Management Agency.

In November, Puerto Rico’s government asked U.S. officials for permission to continue using more than a dozen portable generators for two more years.

Some Puerto Ricans took the latest failure in stride.

“They are part of my everyday life,” said Enid Núñez, 49, who said she ate breakfast before work thanks to a small gas stove she bought for such events.

Meanwhile, Puerto Rico’s Electricity Authority, the island’s largest government agency, is struggling to restructure more than $9 billion in debt.

Petroleum-based power plants generate more than 60% of Puerto Rico’s energy, followed by natural gas and coal. On an island with a poverty rate of over 40%, rooftop solar only accounts for about 7% of electricity consumption.