SAN JUAN, Puerto Rico (AP) — Hurricane Earl battered tiny islands across the northeastern Caribbean with heavy rain and roof-ripping winds Monday as it rapidly intensified into a major Category 4 storm taking a path projected to menace the United States.

Already dangerous with sustained winds of 135 mph (215 kph), Earl was expected to gain more strength before potentially brushing the U.S. East Coast this week and bringing deadly rip currents.

The U.S. National Hurricane Center in Miami warned coastal residents from North Carolina to Maine to watch the storm closely.

“Any small shift in the track could dramatically alter whether it makes landfall or whether it remains over the open ocean,” said Wallace Hogsett, a meteorologist at the center. “I can’t urge enough to just stay tuned.”

In the Caribbean, Earl caused flooding in low-lying areas and damaged homes on islands including Antigua and Barbuda, Anguilla and St. Maarten. Several countries and territories reported power outages. Cruise ships were diverted and flights canceled across the region.