Several governments in the area, including Antigua, Barbuda and St. Kitts and Nevis, have put their territories under tropical storm warning, while Puerto Rico and the US Virgin Islands are under a tropical storm watch, the Miami-based center said.

At 0900 GMT, the center of Chris was located 280 kilometers (174 miles) east of Antigua, packing winds near 65 kilometers (40 miles) per hour. It was tracking west-northwest at 15 kilometers (nine miles) per hour.

Chris is the third Atlantic storm since last year's record-smashing season of 28 named storms, including 15 that became hurricanes.

US weather experts forecast that between eight and 10 hurricanes -- as many as six of them major -- would form in the Atlantic basin during the six-month storm season that started on June 1.