ROME (Reuters) - The United Nations' food aid agency has appealed for more aid to help save lives in Bangladesh where nearly 2,600 people were killed by cyclone Sidr.

"Thousands of poor families have been devastated due to the loss of their crops, livestock and in some cases, family members," said Douglas Broderick of the U.N. World Food Programme.

A 12-person U.N. team is visiting Bangladesh to assess the damage and aid requirements. "The initial assessment reports describe the situation as grim and serious' warranting the launch of a more comprehensive appeal for assistance," the WFP said. It did not specify the amount of aid required.

The food agency has been dropping high energy biscuits from helicopters to people stranded in inaccessible areas. So far it has delivered food aid to 650,000 people.

The government estimates some 3 million survivors who were either evacuated from the low-lying southern coast or whose homes and villages were destroyed will need support.

Aid workers fear inadequate supplies of food, drinking water and medicine could lead to outbreaks of disease.

"We plan to continue our food assistance over the coming weeks and are actively assessing the needs for the coming months," said Broderick.

"We urge donors to step forward to provide immediate funding."

(Reporting by Robin Pomeroy; Editing by Richard Balmforth)