MIAMI, United States (AFP) — Melissa has intensified into a Category 1 hurricane as it charts a worryingly slow course toward Jamaica, the US National Hurricane Center (NHC) said Saturday.

Currently packing winds of 75 miles (120 kilometres) per hour, Melissa is expected to rapidly intensify over the next day into a major hurricane as it creeps toward and across Jamaica, the NHC said in its latest bulletin, warning that Haiti will also see major flash flooding and landslides.

Three people in Haiti have already been killed this week as storm bands from Melissa -lashed the impoverished nation with heavy downpours, provoking landslides.

The storm is expected to move dangerously slowly at it approaches Jamaica from the south, battering the island nation for multiple days before it heads north and threatens eastern Cuba.

Fears are growing that Melissa’s extreme winds and rains could provoke life-threatening floods in the mountainous terrain of eastern Jamaica and western Haiti.

The NHC said it “expected” catastrophic flash flooding and landslides across southwestern Haiti and portions of Jamaica.

The southern Dominican Republic, which shares the island of Hispaniola with Haiti, also faces potential risks of flooding.

Residents in southwestern Haiti should begin “immediate preparations to protect life and property,” the NHC said, warning the storm will likely cause “extensive infrastructural damage and potentially prolonged isolation of communities.”