[Kingston] Hurricane Matthew powered toward densely populated Jamaica and Haiti on Sunday, unleashing winds that could fell homes and power lines and torrential rain that may trigger potentially deadly landslides and floods.
As the Caribbean's worst storm in nearly a decade churned north, dozens of people were trapped on cays - tiny islands - off the coast of Jamaica's main island, officials said.
In Jamaica and elsewhere, authorities scrambled to get buildings protected and people in safe buildings. Jamaicans waited in long lines in stores and at gas stations to stock up. Both airports in Haiti closed.
Jamaica started warning people to evacuate and prepare two days ago. But some on the islands "said they would rather stay to protect their interests," Minister of Local Government Desmond Mackenzie told reporters.
He said the Jamaican Defence Force tried to bring them back to the mainland but they refused gasoline for their boats and dug in.
With winds high and heavy rain started, it was not clear if that force would be able to try again to get the holdouts.
The government was not prepared to put lives of first responders at risk after authorities started advising people as early as Thursday, Mackenzie stressed.
"No turning back now. It is a matter of how long we have to wait this out," he said.
The hurricane was 435 kilometres south southeast of Kingston, at 0000 GMT Monday, with lashing top wind speeds of 230 kilometres per hour, the US National Hurricane Centre said.
Its movement edged up to seven kilometres an houras it churned up from the Caribbean coasts of Colombia and Venezuela.
Briefly a furious Category five hurricane late Friday, Matthew remains a still-dangerous Category four, the strongest to hit the Caribbean since Hurricane Felix in 2007.
In Cuba, President Raul Castro travelled to the southeastern city of Santiago to oversee emergency operations just hours before the hurricane was due to hit.
Matthew had the potential to become a storm for the ages, he warned residents.
"This is a hurricane it's necessary to prepare for as if it were twice as powerful as Sandy," the Cuban leader said, referring to the megastorm that hit with massive destructive force in 2012.
Officials at the US naval base in Guantanamo Bay, Cuba in that same area announced a mandatory evacuation for all non-essential personnel and family members.
On its current forecast track, Matthew's centre will glance past Jamaica on Monday, dumping heavy rain as it makes landfall on Haiti.
Thousands are still living in tents after a massive earthquake in 2010 in Haiti. There, erosion is an especially dangerous problem because of high mountains and lack of trees and brush in areas where they have been cut for cooking.
Matthew is then expected to continue north, tearing across southern and eastern Cuba between Monday and Tuesday as it heads toward the Bahamas.
Forecasts predict the hurricane will dump 40-60 centimetres of rain over southern Haiti with possible isolated maximum amounts of 40 inches.
The storm is also expected to drop 10 to 20 inches of rain over eastern Jamaica, the Dominican Republic, and eastern Cuba with possible isolated maximum amounts of 25 inches.
"This rainfall will likely produce life-threatening flash floods and mudslides," the NHC warned.
Although some Jamaicans brushed off government warnings and weather predictions, many heeded the advisories.
Some Jamaicans complained that they had hunkered down with supplies in the past only to see storms pass by.
"I am tired of wasting my money buying food, gas, boarding up my house," said Michael Franklin, a taxi driver in Montego Bay.
"Then all we get is just a lot of rain and we can't get back our money."
The authorities were placing some 2,000 homeless people in shelters, and the country's garbage collectors were working around the clock to remove waste from streets and open areas, Mr McKenzie said.
The army and reserves were called up to help limit the damage and hospitals throughout the island of almost three million people were standing ready, he added.
There are 900 shelters across the island, he said, 828 of them schools.
Buses were also being sent to flood-prone areas to take residents to shelters.
The US Embassy in Jamaica said it would be closed Monday and Tuesday for consular services. The one in Haiti is also closing those two days.
In Haiti, the authorities increased the alert level from orange to the maximum red late Saturday.
The poorest country in the Americas is home to almost 11 million people, many living in fragile housing.
America's Accuweather website warned meanwhile that Matthew could hit the US East Coast around midweek.
"How significant impacts are along the Atlantic Seaboard will depend on Matthew's strength and proximity to the coast," it said.