HAVANA – Tropical Storm Isaac pushed over Cuba on Saturday after sweeping across Haiti's southern peninsula, where it caused flooding and at least four deaths, adding to the misery of a poor nation still trying to recover from the terrible 2010 earthquake.

Isaac's center made landfall just before midday near the far-eastern tip of Cuba, downing trees and power lines. In the picturesque city of Baracoa, the storm surge flooded the seaside Malecon and a block inland, destroying two homes.

Forecasters said Isaac poses a threat to Florida Monday and Tuesday, just as the Republican Party gathers for its national convention in Tampa. It could eventually hit the Florida Panhandle as a Category 2 hurricane with winds of nearly 100 mph.