Hurricane Maria intensified into a dangerous category five storm and pounded the small island of Dominica as it surged into the eastern Caribbean.
Forecasters warned it might become even stronger.
The storm was following a path that could tomorrow take it near many of the islands recently devastated by Hurricane Irma and then head toward a possible direct strike on Puerto Rico on Thursday.
A series of Facebook posts by Dominica Prime Minister Roosevelt Skerrit captured the fury of the storm as it made landfall on the mountainous island.
"The winds are merciless! We shall survive by the grace of God," Skerrit wrote at the start of a series of increasingly harrowing posts.
A few minutes later, he messaged he could hear the sound of galvanised steel roofs tearing off houses on the small rugged island.
He then wrote that he thought his home had been damaged. And three words: "Rough! Rough! Rough!"
A half hour later, he said: "My roof is gone. I am at the complete mercy of the hurricane. House is flooding."
Seven minutes later he posted that he had been rescued.
It was the first official word from Dominica after the eye wall moved ashore.
Dominica authorities had closed schools and government offices and urged people to move from dangerous areas to shelters.
"We should treat the approaching hurricane very, very seriously," the Prime Minister warned as the storm approached. "This much water in Dominica is dangerous."
In August 2015, Tropical Storm Erika unleashed flooding and landslides that killed 31 people and destroyed more than 370 homes on the small, mountainous island.
Officials on nearby Guadeloupe said the French island would experience extremely heavy flooding and warned that many communities could be submerged.
In Martinique, authorities ordered people to remain indoors and said they should prepare for cuts to power and water. Schools and non-essential public services were closed.
With Puerto Rico appearing destined for a hit, officials in the US territory warned residents of wooden or otherwise flimsy homes to find safe shelter.
"You have to evacuate. Otherwise you're going to die," said Hector Pesquera, Puerto Rico's public safety commissioner. "I don't know how to make this any clearer."
The US territory imposed rationing of basic supplies including water, milk, baby formula, canned food, batteries and flashlights.
The US National Hurricane Centre said Maria had maximum sustained winds of 260 km/h.
It was heading west-northwest at 15 km/h.
"Maria is developing the dreaded pinhole eye," the centre warned.
That was a sign of an extremely strong hurricane likely to get even mightier, said University of Miami hurricane researcher Brian McNoldy. Just like when a spinning ice skater brings in their arms and rotates faster, a smaller, tighter eye shows the same physics, he said.
Maria's eye shrank to a narrow 16km across. "You just don't see those in weaker hurricanes," McNoldy said.
Hurricane warnings were posted for the US and British Virgin Islands, Puerto Rico, Guadeloupe, Dominica, St. Kitts, Nevis and Montserrat.
A tropical storm warning was issued for Antigua and Barbuda, Saba, St Eustatius, St Maarten, St Lucia, Martinique and Anguilla.
The storm's hurricane-force winds extended about 35km from the eye, and tropical storm-force winds as far as 205km. Forecasters said storm surge could raise water levels by 1.8 to 2.7m near Maria's centre.