About 30 of 100 passengers on board were rescued after the collision on Sunday evening and six were in hospital. Rescue teams said they had recovered no bodies in the swirling river as of noon (0600 GMT).

Police said it appeared most of the remaining passengers had managed to swim ashore. Only a small number, they said, may still be unaccounted for though rivers at this time of the year are swollen by monsoon rains and have strong currents. A police official earlier told reporters the ferry, carrying passengers across the river, had been rammed at Narayanganj, 20 km (12 miles) from Dhaka.

Ferry sinkings are relatively common on river routes in Bangladesh, killing hundreds of people every year.