Evacuations were under way across parts of the Caribbean on Sunday as Hurricane Matthew made its way toward land, bringing fierce winds and life-threatening rainfall.
The Category 4 storm was moving north-west toward Haiti and Jamaica, where hurricane warnings were in effect and residents were told to board up their homes and leave costal areas.
The storm's centre was forecast to approach the two countries early Monday, the US National Hurricane Centre said.
Five Cuban provinces were also under a hurricane warning, while hurricane watches were in place in the Bahamas as well as the Turks and Caicos Islands.
Matthew was about 545 kilometres from Port-au-Prince, Haiti, as of 7 am (1200 GMT), with maximum sustained winds of 240 kilometres per hour (kph) and moving at 7 kph.
"Preparations to protect life and property should be rushed to completion," the US hurricane centre advised residents of Jamaica and Haiti, warning that tropical storm conditions would arrive by late Sunday.
Residents in the affected areas were told to expect dangerous storm surges, "life-threatening" flash floods and mudslides.
As much as 100 centimetres of rain could be dumped on parts of Haiti, the poorest country in the Americas and where 80 per cent of the population lives in poverty.
In an address to the nation, Prime Minister Andrew Holness said Jamaica was on "high alert" and that the eastern coast was expected to be hit especially hard.
"I want us to take this hurricane threat seriously and focus on our safety and security. An ounce of preparation saves a pound of recovery," he said.
Ahead of Matthew's arrival, the US Navy ordered the evacuation of all non-essential staff from its base at Guantanamo Bay, Cuba. The remaining military and civilian personnel have been told to shelter in place.
Matthew strengthened to a rare Category 5 storm on Saturday before being downgraded. It caused minimal damage to Colombia and Venezuela last week.