6.3 million people told to evacuate in Florida

Hurricane Irma has strengthened to a category four storm as it nears Florida, with maximum sustained winds of 130mph (209km/h), the BBC reports.

Wind gusts close to hurricane force are already battering islands in Florida's south, with the mainland due to be hit in the coming hours.

Water levels are already rising on the coast of the US state where a huge storm surge is expected.

At least 25 people died when Irma earlier hit several Caribbean islands.

In Florida, 6.3 million people - about 30% of the state's population - had been told to evacuate. But on Saturday, the state governor said it was now too late to leave for anyone remaining.