This image from NOAA was taken at 12:01 a.m. ET Friday. tropical storm Hanna can be seen chugging just east of the Bahamas headed toward the Atlantic coast, where it could bring high winds and rain from South Carolina to Maine. (NOAA/Associated Press)

Authorities along the southeast coast of the United States prepared emergency plans on Friday as forecasters predicted tropical storm Hanna would make landfall some time over the weekend.

The storm laid waste earlier this week to much of the impoverished island nation of Haiti with heavy rains and flooding.

Officials in Haiti said late Thursday the number of those killed by Hanna has risen to 137, up from 61 a day ago, while flood waters have cut off hundreds of thousands of people from receiving critical aid.

As of 11 a.m. ET Friday, Hanna's maximum sustained winds were near 100 kilometres per hour, the U.S. National Hurricane Center said. The storm was centred off the eastern coast of Florida, about 600 kilometres south-southwest of Wilmington, N.C. and moving northwest at nearly 32 km/h.

Forecasters at the Miami-based centre expected Hanna to strengthen only slightly before making landfall early Saturday, though tropical storm watches and warnings remained for much of coastal Georgia, North and South Carolina, and northward as far as Washington D.C and Rhode Island.

Tropical storm warnings mean that tropical storm conditions are expected within the mentioned areas within the next 24 hours, while watches mean the conditions are expected within the next 36 hours.

The governors of Virginia and North Carolina declared states of emergency and officials have urged residents to head inland as Hanna approached. But no mandatory evacuation orders have been issued yet.

The storm snapped telephone cables and caused some flooding in the Bahamas on Thursday, but effectively spared the Caribbean nation from major damage.

The Canadian Hurricane Centre said Hanna could bring wind and rain to the Maritimes on Sunday and Monday.

600,000 need aid in Haiti: UN

This photo released by the United Nations Stabilization Mission in Haiti, MINUSTAH, shows a flooded area of Gonaives, Haiti, on Wednesday. (Marco Dormino/MINUSTAH/Associated Press)Meanwhile, the UN has warned hundreds of thousands are in need of immediate aid from severe flooding in Haiti in the wake of Hanna and a previous tropical storm, Gustav.

Tens of thousands in the area around the flooded region of Gonaives have not eaten in days since Hanna swirled over Haiti for four days bringing heavy downpours that submerged the city in more than two metres of water and effectively cut off the area, aid agencies said.

Freelance reporter Reed Lindsay said he encountered an injured young boy in the city who was fending for himself after his parents drowned in the floods.

"He had a broken leg and had no medical help at all," Lindsay told CBC News on Friday from Gonaives. "He was wearing his underwear. It was the only thing he had left."

Joel Boutroue, the UN's co-ordinator for aid in Haiti, told the BBC that humanitarian organizations were still struggling to reach those affected.

"In Gonaives alone, we have some 70,000 people in shelters, and around 250,000 around Gonaives City need our assistance and that of the government," Boutroue said. "And throughout the country I would say around up to 600,000 people might require our assistance."

Eighty of the deaths occurred in Gonaives and another 22 people died in areas immediately surrounding the port, according to statements released by the Ministry of the Interior and the Civil Protection Department. The remaining 35 deaths were scattered across Haiti, the statements said.

U.S. forecasters warned Hurricane Ike could bring yet more rains and flooding to Haiti next week as the dangerous Category 3 storm moved westward with maximum sustained winds of up to 195 km/h.

With files from the Associated Press