Hurricane Maria headed towards the Virgin Islands and Puerto Rico on Tuesday, with the US National Hurricane Center warning of a "potentially catastrophic" impact as it battered the eastern Caribbean.
"Maria is forecast to remain an extremely dangerous Category 4 or 5 hurricane while it approaches" the British and US territories late Tuesday, the NHC said.
Arriving just as islanders in the region are struggling to recover from devastating Hurricane Irma, which struck earlier this month, Maria claimed its first victim in the French territory of Guadeloupe, where two other people were missing.
The person was killed by a falling tree as powerful winds whipped the archipelago, authorities said, while two more disappeared when their boat went missing in the storm.
On neighboring Dominica, premier Roosevelt Skerrit posted on Facebook that there were initial reports of "widespread devastation" and that the roof of his own home had been blown off.
"We have lost all what money can buy and replace," he said.
The airport and ports have been closed on the tropical island of 72,000 people.
St. Martin, a French-Dutch island that was among the worst hit by Irma with 14 dead, was under a maximum "violet" alert, with people ordered to stay indoors.
A similar measure was in place in the British Virgin Islands.
"Our islands are extremely vulnerable right now," the territory's premier Orlando Smith said in a statement, warning that the storm could turn debris left by Irma into dangerous projectiles.
'Everything is shaking'
Guadeloupe was serving as a base for aid flights to Irma-hit French territories after the hurricane, and there were fears that major damage there could hamper the relief operation.
Authorities said there were few reports of damage to buildings so far, though several areas around the largest city Pointe-a-Pitre were flooded and fallen trees were blocking many roads.
Some 40 percent of households in the territory of 400,000 are without power.
"Everything around me is shaking," former French minister Victorin Lurel told BFMTV from his home in the south of the island.