Stunned residents of the Bahamas surveyed the wreckage of their homes and officials struggled to assess the number killed by Hurricane Dorian, as the storm bore down on the South Carolina coast on Thursday, threatening record flooding.

Some 70,000 people in the Bahamas needed immediate humanitarian relief after the most damaging storm ever to hit the island nation, the United Nations said.

Aerial video of the worst-hit Abaco Islands in the northern Bahamas showed widespread devastation, with the harbor, shops, workplaces, a hospital and airport landing strips damaged or decimated, frustrating rescue efforts.