A state of emergency has been declared in North Carolina as Tropical Storm Florence is expected to gain hurricane strength.

Florence could begin to batter parts of the US East Coast this weekend as the storm swirls across the Atlantic, according to forecasters at the National Hurricane Center.

It is expected to regain hurricane strength as it nears Bermuda, although forecasters said it was too soon to tell where the storm would hit.

Some forecast models showed Florence slamming into land by late next week, while others indicated the storm would curve away from the shore.

North Carolina governor Roy Cooper declared a state of emergency on Friday evening and urged residents to prepare for the worst over the weekend.


He said: "We are entering the peak of hurricane season and we know well the unpredictability and power of these storms."

South Carolina's Emergency Management Division also advised people living on the coast to start making contingency plans.

Hawaii swamped with flooding after hurricane

Hurricane expert Robbie Berg said: "The risk of other direct impacts associated with Florence along the US East Coast next week has increased.

"However, there is still very large uncertainty in model forecasts of Florence's track beyond day five, making it too soon to determine the exact location, magnitude, and timing of these impacts."

A change in atmospheric conditions was expected to allow Florence to regain its former strength.

It had reached major hurricane status on Wednesday and peaked to maximum sustained winds of 130mph.

Two low pressure systems off the coast of Africa behind Florence also had high chances of developing into tropical storms, forecasters said.

"Since we are near the peak of hurricane season, this is a good time for everyone who lives in a hurricane-prone area to ensure they have their hurricane plan in place," forecaster David Zelinsky said.

The National Hurricane Center said Florence's maximum sustained winds on Friday night were estimated to be 60mph.

The storm was centred about 875 miles southeast of Bermuda and moving west at 7mph.

Last month, Hurricane Lane reached 130mph and brought widespread flooding to Hawaii, despite being downgraded to a tropical storm.