PORT-AU-PRINCE – Tropical Storm Tomas re-strengthened to a hurricane on Friday as it headed between Cuba and Haiti, drenching with overnight rain crowded tent and tarpaulin camps housing vulnerable Haitian earthquake survivors.

Although some camp dwellers in Haiti's capital, homeless from the January 12 quake, were able to evacuate to more secure shelter with family or friends, or in schools and public buildings, hundreds of thousands spent the night under dripping plastic and canvas in the mud-choked encampments.

"It rained, but it was a normal night and I slept," said ice cream seller Zaporte N'Zanou, who passed the night in a tent in the big Champs de Mars quake survivors' camp in front of the wrecked presidential palace in Port-au-Prince.

With the approach of Tomas from the south, the United Nations and relief agencies have gone on maximum alert to prepare for the risk of a further humanitarian emergency in Haiti, which is already reeling from a deadly cholera epidemic and from the widespread destruction of the earthquake.

At 8 a.m., Tomas was moving northeastward to the west of Haiti, about 160 miles from Port-au-Prince, packing top sustained winds of 85 miles per hour, the U.S. National Hurricane Center said.

It had earlier re-intensified over the Caribbean sea into a Category 1 hurricane on the five-step Saffir-Simpson scale, heading on a track that would take it near or over eastern Cuba, the Turks and Caicos Islands and southeastern Bahamas.

On Thursday, hours before the approach of the cyclone, Haitian President Rene Preval went on national radio to urge citizens to take precautions and follow evacuation recommendations in the face of the risk of gusting winds, surging waves and torrential rains.