Melissa is categorized as a tropical storm, but "rapid intensification is expected to begin soon," according to a National Hurricane Center forecast issued at 5:00 am (0900 GMT).

The US agency said the storm is forecast to become a hurricane later on Saturday "and a major hurricane by Sunday."

The storm's center is expected to "move near or over Jamaica during the weekend and early next week," it added.

The slow-moving Melissa was located over the central Caribbean Sea before dawn on Saturday, with maximum sustained winds of near 110 kilometers per hour (70 miles per hour).

In Haiti, the Civil Protection Agency said two people died and another was injured Thursday when the tempest triggered a landslide in the west of the island nation.

A falling tree amid downpours earlier in the week had killed an elderly person, the agency said.

The National Hurricane Center warned of "life-threatening and catastrophic flash flooding and landslides" across parts of Jamaica and the southern parts of Haiti and the Dominican Republic.

The storm is also expected to bring heavy rainfall to southeast Cuba.