Tropical Storm Isaac battered impoverished Haiti Saturday, leaving at least one person dead, as southern Florida braced for a possible hurricane during the US Republican convention. With winds of up to 60 miles (95 kilometers) per hour, the storm was expected to sweep over eastern Cuba later Saturday and to become a hurricane on Sunday as it nears Florida, according to the US National Hurricane Center. A hurricane warning was in effect for the Florida Keys and parts of the state\'s southwest coast, the Miami-based NHC said, raising concerns the storm could disrupt the Republican National Convention opening in Tampa on Monday. The forecasters said Isaac was near hurricane strength when the eye of the storm passed over Haiti, where hundreds of thousands of people are still living in squalid, makeshift camps following a catastrophic 2010 earthquake. An eight-year-old Haitian girl died when a wall collapsed at her home, a government official, Gonzague Day, told AFP. She is the first known death related to the storm. Haiti was the poorest country in the Western Hemisphere even before the earthquake killed 250,000 people, and some 400,000 are still living in tent camps in and around the devastated capital Port-au-Prince. Haiti officials said Saturday that more than 3,300 families had been evacuated to temporary shelters, including many from the camps which lack working toilets and safe drinking water. The NHC warned of \"life-threatening flash floods and mud slides\" on the island of Hispaniola -- shared by Haiti and the Dominican Republic -- and tropical storm conditions in eastern Cuba and the Bahamas. Aid groups warned that those without proper shelter after the quake were among the most vulnerable, at risk of disease from water contamination and other disaster scenarios. Oxfam said it was preparing clean water and hygiene kits to help prevent the spread of cholera and other water-borne diseases. \"Nothing short of a miracle can keep people safe from this kind of storm when their only shelter is a tent,\" said the group\'s Haiti director, Andrew Pugh. \"Haiti\'s disaster preparedness and response capacities have improved since the earthquake, but much remains to be done to help the poorest people cope with hurricane-strength threats.\" Isaac was 40 miles (65 kilometers) east of Cuba as it swirled to the northwest at 17 miles (28 kilometers) per hour, the NHC said in its latest bulletin, issued at 11:00 am (1500 GMT). After striking Haiti and southeastern Cuba, home to the US naval base and \"war on terror\" prison at Guantanamo Bay, Isaac was due to head Sunday for the Florida Keys off the southern tip of the United States. In Cuba, the government declared a state of alert in the island\'s six eastern provinces, where nearly five million people live, and evacuated some 5,000 foreign and local tourists from beach-side hotels. Local authorities \"must understand the possible impact of the intense rain on dams, canals and rivers,\" the Cuban civil defense office said, warning of blocked water drainage systems and flooded roads. But officials noted that eastern reservoirs are at very low levels, which helps mitigate the risk of flooding. Isaac could reach Florida early Monday just in time for the Republican convention, when tens of thousands of people will descend on Tampa for speeches, parties and the formal nomination of former Massachusetts governor Mitt Romney to take on President Barack Obama in the November 6 election. City officials have urged residents to prepare for the worst, and Republican National Committee chairman Reince Priebus has expressed concern about the storm, but organizers insisted the show would go on. \"There will be rain and wind on Monday, but the remaining three days of the convention ought to be beautiful. We are prepared for it and we train for this,\" Tampa Mayor Bob Buckhorn told Fox News on Saturday. \"There may be wet shoes, but every day after Monday ought to be fine.\" Vice President Joe Biden has meanwhile canceled a trip to Tampa because of the approaching storm, the Democratic campaign said. In the Gulf of Mexico, BP evacuated its Thunder Horse platform, the world\'s largest offshore production and drilling facility.