MIAMI — Hurricane Irma has strengthened into a Category 4 storm as it approaches the northeast Caribbean.

The storm’s center is 410 miles (660 kilometers) east of the Leeward Islands late Monday afternoon. It has maximum sustained winds of 140 mph (220 kph) and is moving west at 13 mph (20 kph).

Emergency officials are warning that Irma could dump up to 10 inches (25 centimeters) of rain, unleash landslides and dangerous flash floods and generate waves of up to 23 feet (7 meters) as the storm draws closer.

A hurricane warning has been issued for Antigua and Barbuda, Anguilla, Montserrat, St. Kitts and Nevis, St. Martin, Saba, St. Eustatius, St. Maarten and St. Barts, the British and U.S. Virgin islands, Puerto Rico, Vieques and Culebra. A hurricane watch is in effect for Guadeloupe.