MIAMI -- Hurricane Jose became an "extremely dangerous" Category 4 hurricane Friday, threatening Caribbean islands already devastated by Hurricane Irma, the U.S. National Hurricane Center said.

As of Friday afternoon, Hurricane Jose had maximum sustained winds of 150 mph as it moved west-northwest toward the northern Leeward Islands at a speedy 18 mph.

The eye of the storm was located about 380 miles east-southeast from the islands. It was expected to pass near or east of the northeastern Leeward Islands on Saturday.

"I don't think it takes a rocket scientist to know that further damage is imminent," said Inspector Frankie Thomas of the Royal Police Force of Antigua and Barbuda.

Hurricane Irma weakened from a Category 5 to a still-fearsome Category 4 on Friday morning with winds of 155 mph.

The hurricane smashed homes, schools, stores, roads and boats on Wednesday and Thursday as it rolled over some of the world's most famous beach paradises, including St. Martin, St. Barts, St. Thomas, Barbuda and Anguilla.

It knocked out power, water and telephone service, trapped thousands of tourists, and stripped the trees of leaves, leaving an eerie, blasted-looking landscape. Authorities reported looting and gunfire in St. Martin, and a curfew was imposed in the U.S. Virgin Islands.

On the island of St. Thomas, part of the U.S. Virgin Islands, power lines and towers were toppled, leaves were stripped off plants and trees, a water and sewage treatment plant was heavily damaged, and the harbor was in ruins, along with hundreds of homes and dozens of businesses.