The US state of Florida is braced for the imminent arrival of both tropical storm Isaac and the start of the Republican National Convention.
The governor of Florida, Rick Scott, declared a state of emergency ahead of the storm's expected landfall Sunday night in the Florida Keys.
Scott cancelled his appearance at Monday's Republican national convention in Tampa to concentrate on storm preparations, shortly before convention organisers announced that the first day and a half would be shelved to allow time for the storm to pass.
"This is a state that has dealt with hurricanes forever. We are a state where we know we have to get prepared for hurricanes," Scott said.
With tropical storm-force winds extending up to 300 kilometers from Isaac's centre, the area under threat for moderate to substantial damage covers much of southern and western Florida and along the Gulf Coast to Louisiana.
Hundreds of flights have been cancelled in and out of Miami, Fort Lauderdale and other southern Florida airports.
The US Bureau of Safety and Environmental Enforcement said about 24 percent of the Gulf of Mexico's oil production and eight percent of its gas output had been shut off as a precaution.
The storm has already claimed several lives in Haiti on its path through the Caribbean. Forecasters at the National Hurricane Center in Miami said it was too soon to predict where Isaac would make its second landfall, probably in the early hours of Wednesday.
There is also a chance it may hit New Orleans on the seventh anniversary of the devastating Hurricane Katrina.
jm/pfd (Reuters, AP)