Battered and reeling from Hurricane Irma, isolated Caribbean islands lacking infrastructure, communications, medical supplies and other essentials prepared to weather another potent hurricane, Jose, as it bore down on the region Saturday.

Jose was headed toward the northern Leeward Islands, which include Antigua and Barbuda, St. Martin and the U.S. and British Virgin Islands, with sustained winds of 145 mph — a Category 4 storm.

Irma already this week left a trail of flooded streets, toppled buildings, uprooted trees, upside-down boats and cars, and residents and visitors scrambling to secure shelter, food and clean water. Many people were looking for ways off the islands.

Irma has killed more than 20 people across the Caribbean. Drone and helicopter footage show it flattened homes, businesses, and lush tropical vegetation. It's expected to hit South Florida early Sunday.

Ahead of Jose's expected arrival later Saturday in Barbuda, Prime Minister Gaston Browne ordered the emergency evacuation of that island's entire population, about 1,600 people, to neighboring Antigua, which was spared the brunt of Irma. An estimated 95 percent of all buildings in Barbuda have been destroyed.

In St. Martin, an island dually governed by France and the Netherlands, Peter Jan de Vin, a Dutch military commander, tweeted a picture of marines dropping flyers from a helicopter warning people that they need to find shelter before Jose's potentially destructive winds descend on the island.

The Dutch government says 70 percent of the homes on its part of the island were damaged or destroyed in Irma, leaving many residents dependent on public shelters as they brace for the next storm.

Dutch Prime Minister Mark Rutte said looting broke out on the island. About 230 Dutch troops and police are patrolling, and another 200 are on the way, he said.

A state of emergency was called in the British Virgin Islands, an archipelago of about 70 islands and small cays with 35,000 people, where the Caribbean Disaster Emergency Management Agency said four people were killed due to Irma. Because of the sheer devastation to the BVI, information has been hard to come by and authorities cautioned the death toll may rise.

A Facebook group called BVI Abroad — Hurricane Irma was filled with posts urgently seeking information about missing friends and family members, images and video of the destruction, updates on the emergency response, and with pleas for authorities and volunteers to get more help for people stranded in hard-to-reach areas.

"We have enough fresh water for all of us to survive for two weeks, if we ration," Catherine Clayton, whose family owns an eight-room hotel in Josiah's Bay, a relatively remote corner of the largest BVI island Tortola, told the New York Times.

"Same for food."

Posts to the BVI Abroad — Hurricane Irma Facebook group expressed anger and frustration at the perceived slow response by the British government, which has pledged $42 million and 20 tons of aid to the Caribbean in the form of shelter kits, solar lanterns and other humanitarian relief supplies, but whose efforts have appeared to lack coordination.

In the U.S. Virgin Islands, where four people died, U.S. military and the Federal Emergency Management Agency were providing relief on the ground but utilities remain badly affected and the roof of the only hospital in St. Thomas was blown away.

The state of devastation in Cuba, which Irma pummeled through early Saturday, was not known. Cuban authorities reported significant damage, but no deaths, according to the AFP news agency.