Hurricane Fiona pounded Puerto Rico over the weekend as residents braced for another day without power as unrelenting rainfall brought widespread flooding and caused damages that the island’s governor called "catastrophic."

The National Weather Service (NWS) in San Juan warned of ongoing flash flooding across the island early Monday and urged residents to "move to higher ground immediately."

Parts of Puerto Rico were inundated with as much as 22 inches of rain on Sunday, the NWS tweeted. Up to 30 inches of rain was forecast for Puerto Rico's southern region on Monday.

With rain still pounding the island, flash flood warnings remained in place until 2 p.m. local time for Aibonito, Arroyo, Cayey, Coamo, Guayama, Juana Diaz, Ponce, Salinas, Santa Isabel and Villalba Counties.

HURRICANE FIONA MAKES LANDFALL IN DOMINICAN REPUBLIC AFTER HITTING PUERTO RICO

Hurricane Fiona flood waters submerging home

A home is submerged in floodwaters caused by Hurricane Fiona in Cayey, Puerto Rico, Sunday, Sept. 18, 2022.  According to authorities three people were inside the home and were reported to have been rescued.  (AP Photo/Stephanie Rojas)

While no deaths have been reported, authorities in the U.S. territory said it was too early to know the full scope of damage.

"The damages that we are seeing are catastrophic," said Gov. Pedro Pierluisi.

President Biden tweeted early Monday, writing that both he and First Lady Jill Biden were keeping the people of the island in their prayers. Biden had declared a state of emergency on the island Sunday as the eye of the storm approached its southwest corner.

Hundreds of people across the island have been evacuated or rescued, with nearly 1,300 spending the night in shelters.

While the storm had knocked out power to nearly the entire island of 3.2 million people, authorities announced Monday that power had been returned to 100,000 customers. Power distribution company Luma said it could take days to fully restore service.

Hurricane Fiona floods roadway

A road is flooded by the rains of Hurricane Fiona in Cayey, Puerto Rico, Sunday, Sept. 18, 2022. (AP Photo/Stephanie Rojas)

At the height of the storm, Fiona ripped asphalt from roads and washed away a bridge in the central mountain town of Utuado that police said was installed by the National Guard after Hurricane Maria hit in 2017 as a Category 4 storm. The storm also tore the roofs off homes, including that of Nelson Cirino in the northern coastal town of Loiza.

Hurricane Fiona aftermath features muddy road with people cleaning debris

People clean debris from a road after a mudslide caused by Hurricane Fiona in Cayey, Puerto Rico, Sunday, Sept. 18, 2022. (AP Photo/Stephanie Rojas)

Fiona was centered 35 miles southeast of Samana in the Dominican Republic, with maximum sustained winds of 90 mph on Monday morning, according to the U.S. National Hurricane Center. It was moving to the northwest at eight mph.

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As much as 15 inches were projected for the eastern Dominican Republic, where authorities told most people to stay home from work and banned the use of beaches.

The Associated Press contributed to this report.