President Barack Obama has declared a state of emergency in Louisiana, as Tropical Storm Isaac threatens to hit the US as a category two hurricane.
Isaac is heading for New Orleans, possibly as early as Tuesday night, nearly seven years to the day after Hurricane Katrina devastated the city.
The Republican Party has delayed by a day the start of its national convention in Tampa, Florida.
Isaac killed at least 20 people in Haiti and the Dominican Republic.
The storm wrought significant flooding and damage in the Caribbean.
Late today, the National Hurricane Center (NHC) warned Isaac could reach category two strength, with top winds of 100mph (160km/h). The forecast was revised up from category one.
President Obama approved Louisiana’s request for a federal disaster declaration, making available federal funds for recovery activities such as clearing debris.
Earlier, the governors of Louisiana, Florida, Mississippi and Alabama declared emergencies in their states. (BBC)
