Washington, 31 December 2024 (dpa/MIA) - The US territory of Puerto Rico has suffered a massive power outage on New Year's Eve.

Almost 90% of customers of the Caribbean island's power grid operator, LUMA, were affected, the firm said on Tuesday.

According to media reports, it could take several days before the electricity supply is fully restored.

The cause of the blackout may have been a problem in a substation, a spokesman for the energy supplier Genera PR said, according to local media. The disruption may have led to a chain reaction in which several power plants failed.

Experts are in the process of determining the exact cause and checking how the grid can be restarted.

Puerto Rico, with 3.2 million inhabitants, is the largest of the United States' overseas territories.

Although its residents are US citizens, they are not allowed to take part in US presidential elections, and their delegates in Congress in Washington have no voting rights.

The island has a notoriously unstable power grid. Its infrastructure is still suffering from the devastating effects of Hurricane Maria, which killed almost 3,000 people in 2017.

More recently, Hurricane Ernesto caused widespread power outages in Puerto Rico in August.

MIA file photo