Forecasters at the National Hurricane Center in Miami said at 11 p.m. EDT Gustav was about 35 miles west-southwest of Kingston, Jamaica, and about 275 miles east-southeast of Grand Cayman. The storm was moving toward the west at about 7 mph and a turn toward the west-northwest and northwest was expect during the next two days.

A hurricane watch was in effect for all of the Cayman Islands.

"Gustav could become a hurricane at any time," the report said.

Sustained winds were 70 mph, just below the hurricane threshold of 74 mph, and winds extended 60 miles from the center.

Forecasters warned of coastal storm surge flooding of 1 to 3 feet above normal tide levels and as much as 12 inches of rain for Jamaica and the Cayman Islands.

Forecasters said the storm would likely regain hurricane status as it moved over warm waters toward the west at 5 mph Thursday afternoon.

While Gustav's ultimate path wasn't certain, Louisiana Gov. Bobby Jindal declared a state of emergency Wednesday and mobilized 3,000 National Guard troops, The Times-Picayune newspaper in New Orleans reported.

In Washington Thursday, White House spokeswoman Dana Perino told a news conference President George Bush was "involved, engaged and getting briefings and working to make sure that the federal assistance is there."