About 100 people survived, but more than 200 people are known to have died in the disaster.

The BBC's David Chazan: Little hope of more survivors

Officials also say the ferry was not licensed to carry passengers on the section of the River Meghna where the accident occured.

All passenger traffic on the river has been suspended until October, when the rainy season ends.

Strong currents

Bangladeshi ferries are notoriously overcrowded

The accident happened near the town of Lakshmipur, 175km (110 miles) from the capital, Dhaka, in a stretch of river more than 14km wide with strong currents.

The vessel was believed to have been heading for Lakhsmipur from Barisal, further south.

Some survivors said the boat was swamped by three huge waves, while others said it had been caught in a whirlpool.

Reports said the boat was carrying between 300 and 400 people - roughly double its capacity. The passengers were mostly farmers.

People were thrown overboard as the ferry turned over. Fishing boats picked up more than 100 survivors, but most of the others are unaccounted for.

Tropical storm

"The ferry tilted on one side and sank in midstream immediately after being caught in a tropical storm at 1100 (0500GMT)," one survivor was quoted as saying.

"The ferry was overcrowded and was running at speed in heavy current," he added.

The BBC correspondent in Dhaka, David Chazan, says such disasters happen several times a year in Bangladesh.