CHARLESTON/MARSH HARBOUR, United States - North Carolina braced for a "long night" of strong winds and driving rain as Hurricane Dorian moved near the US state's coast on Friday after devastating the northern Bahamas, where it left at least 30 people dead and thousands homeless.

Authorities in the state of Florida - which was largely spared by the storm - blamed six more deaths on the hurricane, US media reported, though they occurred as the victims were preparing for the storm's arrival or were evacuation-related.

"Dorian should remain a powerful hurricane as the center moves near or along the coast of North Carolina," the Miami-based National Hurricane Center, or NHC, said on Friday morning, after downgrading it to a Category 1 storm.

It warned that although weakening, the hurricane was still packing winds of 150 kilometers per hour, with some areas of the Carolina coast forecast to see dangerous storm surges of up to 2.1 meters and between six and 12 inches of rain.

"We know we're in for a long night and we'll be eager to see the sunshine in the morning," North Carolina's Governor Roy Cooper told CNN on Thursday night.

The slow-moving monster storm also spawned several tornadoes but there were no immediate reports of casualties.

US President Donald Trump said on social media that he had spoken to the governors of North and South Carolina, telling them he is "ready to assist".

Dorian was a Category 5 hurricane - the highest on the five-level wind scale - when it slammed into the northern Bahamas on Sunday, leaving a trail of immense destruction.

The full extent of the damage in the northern Bahamas was becoming known on Thursday as rescue teams fanned out searching for survivors and bringing relief to victims.

Bahamas' Prime Minister Hubert Minnis told CNN that at least 30 people were killed in the storm, which caused what he called "generational devastation".

The death toll is expected to rise as an international humanitarian effort to help the Caribbean country gains momentum.

The United Nations announced the purchase of eight tons of ready-to-eat meals and said it will provide satellite communications equipment and airlift storage units, generators and prefab offices to set up logistics hubs. UN humanitarian chief Mark Lowcock said about 70,000 people "are in immediate need of lifesaving assistance" on Grand Bahama and Abaco.

A British Royal Navy ship docked at Abaco and distributed supplies to hurricane survivors. On Grand Bahama, a Royal Caribbean cruise ship dropped off 10,000 meals, 10,000 bottles of water and more than 180 generators, as well as diapers and flashlights.

American Airlines said it flew a Boeing 737 from Miami to Nassau to drop off 14,000 pounds of relief supplies. The airline is also giving frequent-flyer points to customers who donate at least $25 to the Red Cross.

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