SAN JUAN, Puerto Rico -- Hurricane Earl lashed the northeastern Caribbean on Monday as it grew into a Category 4 storm, tearing roofs off buildings and cutting power to islanders on a course that could threaten the eastern United States this week.
The U.S. National Hurricane Center in Miami said Earl, which formed on Sunday, was already a major hurricane and it was likely to keep gaining force.
"Interests from North Carolina all the way to Maine should keep an eye on the system," said Jessica Schauer, a meteorologist at the Hurricane Center.
The storm's center was forecast to pass over or near the northernmost Virgin Islands later Monday as it gradually turns to the north before running roughly parallel to the U.S. East Coast.
The Hurricane Center said it is early to say what effect Earl would have on the U.S., but warns it could at least kick up dangerous rip currents. A surfer died in Florida and a Maryland swimmer has been missing since Saturday in waves spawned by now-weakening Hurricane Danielle.
Earl's eye passed just north of the tiny British territory of Anguilla, where police said the wind blew the roofs off buildings and damaged utility poles.
"The winds are whistling outside," said Martin Gussie, a police officer involved in coordinating the emergency response. "When the gusts of wind come, each time it sounds stronger."
In Antigua, wind and rain destroyed at least one home, though there were no reports of critical injuries. Emergency response officials said about 350 people were in shelters. Local weather authorities reported at least 5 inches of rain and 10-foot waves.
In St. Maarten, the storm toppled trees, damaged roofs and knocked out electricity to much of the island. Heavy gusts of wind swirled debris across streets that were empty due to a government-imposed curfew.
Alisha Daya, a 24-year-old tourist from Milwaukee, said she wore earplugs Sunday night but still had trouble sleeping because of the noise from the wind and crashing waves at the Oyster Bay Beach Resort in St. Maarten.
"It was loud because we were right on the ocean," said Daya, who said the storm will keep her and her parents and boyfriend from leaving the island as planned on Monday although the worst seemed to have passed. "Some furniture is flying around, but everything seems to be OK."
Cruise lines diverted ships to other ports, and flights were canceled across Puerto Rico and the eastern Caribbean.
The projected track had the storm passing close to or over the British Virgin Islands. In Anegada, the territory's northernmost island with a population of about 280 people, 58-year-old Lila Elly Ali and her son were nailing shut the doors of her century-old, wooden house as the wind began picking up.
"They say the eye of the storm is supposed to come close to us, so we've just got to pray. Everyone here is keeping in touch, listening to the radio," she said.
At the El Conquistador Resort in Fajardo, Puerto Rico, a long line of people waited at the reception desk -- as the lights occasionally flickered -- to check out and get to the airport, where they faced more delays.
John and Linda Helton of Boulder, Colorado, were waiting it out. The couple, celebrating their 41st wedding anniversary, finished a Caribbean cruise on Sunday and planned to spend three days in Puerto Rico.
"There was a huge line of people checking out as we were coming in and I thought it was just that summer vacation must be over," said John Helton, a real estate appraiser. "But we paid for the room so we might as well stick it out."
Besides, "I don't think we could get a flight even if we wanted to leave," his wife added.
The U.S. Virgin Islands imposed a curfew from 6 p.m. Monday to 5:30 a.m. Tuesday for the islands of St. Thomas and St. John. Police Commissioner Novelle Francis said anyone found on the street during those hours without a pass will be taken into custody.
Hurricane warnings were in effect for Anguilla, St. Martin, St. Barthelemy, St. Maarten, Saba, St. Eustatius, the British Virgin Islands, the U.S. Virgin Islands and the Puerto Rican islands of Culebra and Vieques.
By late Monday morning, Earl was about 140 miles east of San Juan and headed west-northwest at 15 mph, according to the center in Miami. Hurricane-force winds extended outward up to 60 miles from its center.
Earl has grown rapidly in strength, fueled by warm ocean temperatures of 86 F.
Earl could bring battering waves and storm surges of up to four feet above normal on some islands, as well as downpours that threaten to unleash flash floods and mudslides.
Forecasters say there is a chance the hurricane could brush the U.S. Mid-Atlantic region toward the end of the week, with its closest approach to North Carolina on Thursday or Friday.
Meanwhile, the Category 1 Hurricane Danielle was weakening far out over the north Atlantic.