KINGSTON, August 28, 2008 (AFP) - Tropical Storm Gustav homed in on Jamaica Thursday after claiming some two dozen lives in Haiti and the Dominican Republic, with officials here opening emergency shelters and urging coastal residents to head to higher ground.

'Gustav could become a hurricane before moving over Jamaica,' the US-based National Hurricane Center said in a statement, after the government of Jamaica issued a hurricane warning for island.

In addition to issuing dire warnings to inhabitants of flood-prone areas, officials here suspended government-run bus service in anticipation of the storm's arrival. Motorists began to clear the roads of traffic while businesses shuttered and boarded up their storefronts.

Meanwhile, the southern US state of Louisiana also was battening down, amid warnings that hurricane-scarred Gulf coast could be struck early next week by Gustav, the worst storm since Katrina leveled the region almost exactly three years ago.

The storm at 1500 GMT was packing maximum sustained winds of 70 miles (110 kilometers) per hour and was expected to become more powerful 'during the next couple of days,' the NHC said.

The hurricane center said Gustav was centered about 45 miles (75 kilometers) east of Kingston, moving west at about five miles (seven kilometers) per hour and is expected to reach Jamaica sometime during the day Thursday, before moving on to the tiny British overseas territory Cayman Islands Friday.

Gustav struck the island of Hispaniola, shared by the Domincan Republic and Haiti, as a Category One hurricane on Tuesday.

The storm is expected to produce rainfall of as much as 25 inches in some areas, which was likely to produce life-threatening mudslides, flash floods and tidal flooding of as much as three feet (one meter) above normal levels.

Cuba is also on track to be hit by the storm, especially the western side of the island according to the most recent forecasts.

Forecasts have it passing south of Jamaica as a tropical storm and reaching Grand Cayman Island as a hurricane later in the week before passing between Mexico's Yucatan peninsula and Cuba's western tip, the center said.

News that Gustav could reach the Gulf of Mexico early next week worried industry analysts.

'Even if the damage from the approaching storm is fractional, it could still be significant,' said Mike Fitzpatrick, an oil industry analyst at firm MF Global.

'Sparse capacity means that every barrel of oil lost to the marketplace will be felt, particularly as the northern hemisphere's winter is just around the corner,' he said.

With memories of the devastation caused by Hurricane Katrina in 2005 still fresh, US federal and Louisiana state authorities prepared for the worse to avoid repeating the slow disaster response of three years ago.

Louisiana Governor Bobby Jindal declared a state of emergency Wednesday and announced plans to begin evacuating coastal areas ahead of the storm.

'As long as there is a chance that we'll be in this storm, I'll be here in Louisiana,' said Jindal, warning he may miss next week's Republican National Convention to name John McCain the party's presidential nominee.

The US Department of Homeland Security urged Gulf Coast residents to get ready for the storm.

'Regardless of its predicted path, it is important for citizens in the Gulf Coast region to listen to what their local officials are advising over the course of the next few days and to take these simple steps to prepare,' said Homeland Security Secretary Michael Chertoff.

New Orleans Mayor Ray Nagin, who was criticized for his administration's botched response to Katrina, made plans to leave the Democratic National Convention early so he could also help the city prepare for the storm.

The NHC also announced that a new tropical storm, Hanna, is brewing in the Atlantic, the eighth so far this hurricane season.