Storm Irene Becomes Hurricane over Puerto Rico

Tropical Storm Irene gained strength as it passed over Puerto Rico early Monday and was officially declared a hurricane, U.S. government forecasters said.

The hurricane, whose eye was located 25 miles (40 kilometers) west of San Juan, now packed sustained winds of 125 kilometers an hour, the Miami-based National Hurricane Center announced.

Irene was expected to become even stronger as it moves north northwest at about 19 kilometers an hour, the center warned.

"On the forecast track the center of Irene will move off the north coast of Puerto Rico this morning and move near or over the northern coastal regions of the Dominican Republic this afternoon or tonight," the forecast said.