The government officials put the toll to over 260 and said it was likely to rise sharply.
Unofficial reports said the toll could be more than 1000. The worst affected district is Barguna where unofficial sources said at least 450 people were killed.
At a press conference, Disaster Management Secretary Ayub Mian said, "there are remote areas and offshore islands where rescuers could not reach yet". He said the Barguna toll was yet to be confirmed.
At least 500 trawlers with over 3000 fishermen have been missing since cyclone Sidr, packing winds upto 240 kms, made landfall at Khulna-Barisal coast last evening and swept central Bangladesh, including the capital Dhaka.
Almost the entire country plunged into darkness with the collapse of national grid. Power department official said they could restore power supply in only 10 per cent of the areas. They are expecting to restore the normal power supply within next two days.
The power failure affected the transport system, water supply and telephone operations.
The Army backed by air force choppers was called in to help in rescue efforts.
Other areas devastated in the cyclone included Dublar Char, an island in the Subdarbans forest, and districts of Khulna and Barisal.
