Puerto Rico's governor declared a state of emergency on Monday ahead of powerful Hurricane Irma, which has strengthened into a Category 4 storm.

The National Guard was also activated as the U.S. territory prepares for the storm to hit on Wednesday, the U.S. National Hurricane Center said.

“Despite the economic challenges Puerto Rico is facing, the approved budget has $15 million for the emergency fund,” Gov. Ricardo Rosselló said in a statement.

Government workers on the islands of the eastern Caribbean are clearing drains and pruning trees as authorities urge residents to prepare for Hurricane Irma, a Category 4 storm likely to begin buffeting that area Tuesday.

Emergency officials warned that the storm could dump up to 10 inches of rain, unleash landslides and dangerous flash floods and generate waves of up to 23 feet 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.

"We're looking at Irma as a very significant event," Ronald Jackson, executive director of the Caribbean Disaster Emergency Management Agency, said by phone. "I can't recall a tropical cone developing that rapidly into a major hurricane prior to arriving in the central Caribbean."

A hurricane watch was in effect for Puerto Rico, Vieques, Culebra, the British and U.S. Virgin islands and Guadeloupe. A tropical storm watch was issued for Dominica.



Long-range forecasts indicated Irma likely would curve to the northwest beginning late Monday and skirt to the north of the islands in the eastern Caribbean on a path that could potentially take it to the U.S. East Coast, but it was too early to make a definitive prediction.

The Category 4 storm was moving west-southwest at 13 mph with maximum sustained winds up to 130 mph, according to the U.S. Hurricane Center. The storm was centered about 490 miles east of the Leeward Islands.



The Associated Press contributed to this report.