Tropical Storm Isaac is expected to strengthen Sunday as it moves away from the Florida Keys and enters the Gulf of Mexico, posing a threat to a vast stretch of coast, including New Orleans, the National Hurricane Center, or NHC, said.

Isaac was about 130 kilometers (80 miles) southeast of Key West, Florida, and some 180 kilometers (110 miles) east-northeast of Havana at 11:00 a.m. (1500 GMT), the NHC said in its latest bulletin.

The storm, which has maximum sustained winds of 100 kph (62 mph), is moving west-northwest at 30 kph (18 mph), the NHC said.

The hurricane watch from Golden Beach to Ocean Reef on Florida's east coast has been discontinued.

The hurricane watch on the Louisiana coast has been extended to just east of Morgan City, including the New Orleans metro area and Lake Pontchartrain.

A hurricane warning is in effect for the Florida Keys, including the Dry Tortugas, as well as on the west coast of Florida from Bonita Beach south to Ocean Reef and Florida Bay.

Tropical Storm Isaac is expected to intensify as it veers toward the northwest and slows in the next 48 hours, gaining strength over the warm waters of the Gulf of Mexico.

"The center of Isaac is expected to move near or over the lower Florida Keys later today and tonight ... and move into the eastern Gulf of Mexico on Monday," the NHC said. "Isaac is expected to be at or near hurricane strength when it reaches the Florida Keys."

The storm killed at least six people in Haiti, where more than 14,000 other people have been evacuated in six of the country's 10 departments, officials said.

Isaac also damaged houses and farmland in the Caribbean nation.

More than 20,000 people have been evacuated in Cuba, where Isaac caused flooding in coastal areas, made rivers overflow their banks, downed power lines and damaged houses.

The forecast track for Isaac, whose winds extend outward 335 kilometers (208 miles) from the center, has shifted slightly to the west, the NHC said.

The change in the storm's track reduces the threat to Florida's east coast, including Miami, and increases it for the Gulf coast, especially New Orleans, which was devasted by Hurricane Katrina in late August 2005.

The storm poses a threat to Louisiana, Mississippi, Alabama and the Florida Panhandle. EFE