Hurricane Irma, one of the strongest storms ever recorded in the Atlantic, hit the eastern Caribbean on Wednesday with winds of up to 185 miles an hour, but had slowed to 180 m.p.h. by Thursday morning.

• The Category 5 storm leveled Barbuda, damaging 95 percent of its buildings and leaving the island “barely habitable.” It has since begun lashing Puerto Rico and is also threatening havoc and destruction in the Virgin Islands, the Dominican Republic, Haiti and Cuba. The Bahamas and the Turks and Caicos Islands will also be at risk on Thursday.

• The French interior minister, Gerard Collomb, said at least eight people had been killed in French Caribbean territory, and at least three deaths were reported elsewhere. The authorities warned that the toll would rise as communications improved. ‘Barbuda is literally rubble,’ but Antigua is spared.

Early on Wednesday, Prime Minister Gaston Browne of Antigua and Barbuda said his nation had been spared the worst of the hurricane, declaring in a statement, “The essential point is that our main infrastructure has stood up and our country can resume normal life within hours.” He went so far as to add, “I dare to say that no other country in the Caribbean would have been as well prepared as we were.”

This turned out to be stunningly inaccurate: While the damage in Antigua was not as severe as expected, Mr. Browne announced in the afternoon that 95 percent of all structures on its sister island, Barbuda, had been damaged or destroyed, rendering the island “barely habitable.” A telecommunications tower was broken in two. At least one person, an infant, was killed.

Barbuda, home to about 1,600 people (3 percent of the country’s population), “is literally rubble,” the prime minister told ABS TV/Radio Antigua. In his initial statement Wednesday morning, Mr. Browne suggested he had been receiving reports from Barbuda. But he later clarified that, in fact, the storm had knocked out all official communication systems on the island, rendering officials there unreachable after the storm. As a result, it was not until the afternoon, when the prime minister surveyed Barbuda from the air, that the extent of the devastation became clear.

“What I saw was heart-wrenching — I mean, absolutely devastating,” Mr. Browne told ABS TV afterward, estimating that it would take at least $150 million to return the island to some semblance of normalcy.

“Hurricane Irma would have been easily the most powerful hurricane to have stormed through the Caribbean,” he said, “and it is extremely unfortunate that Barbuda was right in its path.”

Mr. Browne said he had been caught off guard by the utter destruction in Barbuda because it is so close to the comparatively unscathed Antigua. The islands are less than 40 miles apart.

— CARL JOSEPH, KIRK SEMPLE and MAGGIE ASTOR
‘Considerable’ damage in the French Caribbean.

President Emmanuel Macron of France said on Wednesday evening that it was too early to say how badly the islands of St. Martin and St. Barthélemy had been damaged or how many casualties there were. But French officials reported that the death toll was at least two, and Mr. Macron said the aftermath would be “harsh and cruel.”

“We will have victims to lament, and the material damage on the two islands is considerable,” he said after a crisis meeting in Paris, adding that the “entire nation” stood beside the inhabitants of the islands.

Mr. Macron said that emergency services were focusing on re-establishing contact with the affected areas and that rescue operations would be coordinated from the French Caribbean island of Guadeloupe, where the French minister for overseas territories, Annick Girardin, was headed on Wednesday evening.