(CNN)[Breaking news update, published at 9:09 a.m. ET]
At least 18 people have died in incidents related to Hurricane Irma, officials said. The deaths, all on Caribbean islands, include nine in French territories, one at the British overseas territory of Anguilla, one on Barbuda, four on the US Virgin Islands, and three in Puerto Rico.
[Original story, published at 8:50 a.m. ET]
Hurricane Irma hurtled north of the Caribbean on Friday, leaving catastrophic damage in its wake as it closed in on Florida, where it could slam into Miami this weekend.
The storm churned in the Atlantic between southeastern Cuba and the Turks and Caicos Islands on Friday morning, and is expected to move west toward central Cuba and the Bahamas.
Irma was downgraded to an "extremely dangerous" Category 4 storm on Friday, with winds reaching a sustained maximum of 150 mph, the US National Hurricane Center said. At its peak, Irma sustained maximum wind speeds of 185 mph or above for longer than any storm ever recorded in the Atlantic basin.
At least 10 people were killed as Irma pummeled small northeastern Caribbean islands such as Barbuda and St. Martin. In Puerto Rico, hundreds of thousands people were left without power.