The first tropical depression of the 2006 Atlantic hurricane season has formed in the Caribbean Sea, forecasters have said. The weather system could strengthen to become the season's first named storm.

There are warnings of heavy rain, flash floods and mudslides in Cuba, the Cayman Islands and western Florida.

The 2005 season was the most destructive on record with 15 hurricanes including Katrina, blamed for deaths of more than 1,300 people.

The US Climate Agency says this year is expected to be "above normal" but less active than last year.

Between 13 and 16 named storms have been predicted, of which four will be "major storms" of category three or above.

The US hurricane season started on 1 June and lasts until 30 November.

The depression was detected 80km (50 miles) southwest of Cuba's western tip at 1300 GMT, moving northwest at 19km/h.

Tropical storm warnings have been issued for the Cuban provinces of Pinar del Rio and Isle of Youth.

"Some strengthening is forecast during the next 24 hours, and the depression could become a tropical storm later today," the US National Hurricane Center said in an advisory.