SAN JUAN, Puerto Rico -- Hurricane Maria's destruction has set Puerto Rico back decades, even as authorities worked to assess the extent of the damage, Puerto Rico's nonvoting representative in the U.S. Congress said Sunday. 

"The devastation in Puerto Rico has set us back nearly 20 to 30 years," said Puerto Rico Resident Commissioner Jenniffer Gonzalez. "I can't deny that the Puerto Rico of now is different from that of a week ago. The destruction of properties, of flattened structures, of families without homes, of debris everywhere. The island's greenery is gone."

Engineers on Sunday planned to inspect the roughly 90-year-old Guajataca Dam, which holds back a reservoir covering about 2 square miles in northwest Puerto Rico. The government said it suffered a large crack after Maria dumped 15 inches of rain on the surrounding mountains and that it "will collapse at any minute." Nearby residents had been evacuated, but began returning to their homes Saturday after a spillway eased pressure on the dam.

Puerto Rico's National Guard diverted an oil tanker that broke free and threatened to crash into the southeast coast, said Gov. Ricardo Rossello, and officials still had not had communication with nine of 78 municipalities.

"This is a major disaster," he said. "We've had extensive damage. This is going to take some time."

Hurricane Maria: Category 2 storm -- latest path, forecast

The U.S. National Hurricane Center (NHC) released its Sunday evening advisory to report that Hurricane Maria remains a Category 2 storm and that its core will move well east of the southeast coast of the United States during the next day or so. Tropical storm and storm surge watches are in effect for a portion of the coast of North Carolina.

As of 5 p.m. ET, Hurricane Maria is about 425 miles south-southeast of Cape Hatteras and is moving about 9 mph with maximum sustained winds of 105 mph with higher gusts. NHC says Maria is a large hurricane and hurricane-force winds extend outward up to 60 miles from the center.

A look at Hurricane Maria's path as forecasted by the U.S. National Hurricane Center on Sun., Sept. 24, 2017. U.S. National Hurricane Center

The death toll from Maria in Puerto Rico was at least 10, including two police officers who drowned in floodwaters in the western town of Aguada. That number was expected to climb as officials from remote towns continued to check in with officials in San Juan. Authorities in the town of Vega Alta on the north coast said they had been unable to reach an entire neighborhood called Fatima, and were particularly worried about residents of a nursing home.

Across the Caribbean, Maria had claimed at least 31 lives, including at least 15 on hard-hit Dominica.

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