Hurricane Matthew continued to batter the east coast of the US state of Florida with its eye just kilometres offshore, as some 600,000 homes in the state were left without power.
One of the hardest-hit areas is Brevard County, located east of Orlando on Florida's coast, where about 146,000 homes are without electricity, Governor Rick Scott said.
US President Barack Obama on Friday urged citizens to listen to local authorities, and warned that storm surge remained an ongoing threat.
The centre of the storm is moving north-north-west at a speed of 19 kilometres per hour (kph) and is expected to continue its path along the coast over the course of Friday, the Miami-based National Hurricane Centre said.
As of 1500 GMT, the centre of the storm was located 155 kilometres south-east of the northern Florida city of Jacksonville.
Matthew is expected to turn to the north Friday night or Saturday, with the centre of the storm moving along the coast of the states of Georgia and South Carolina on Saturday.
The hurricane weakened slightly overnight and was downgraded to a Category 3 hurricane Friday morning. It has maximum sustained winds of 195 kph and is expected to remain a Category 3 hurricane as it moves along the coast of Florida and into Georgia and the Carolinas.
Hurricane warnings now extend into North Carolina. Millions of people have already evacuated coastal areas of the three states in the south-eastern United States ahead of the arrival of the storm.
In Haiti, Matthew had killed at least 283 people just in the worst affected area of Department Sud, Radio Television Caraibes reported, citing local officials.
The Vatican sent a consolatory message to Haiti, saying Pope Francis "expresses his sadness and offers his prayer to all those who have lost a loved one. He sends them his heartfelt condolences and assures them of his deep sympathy in these painful circumstances."