A passenger bus plunged into a river near the Bangladeshi capital Dhaka on Sunday, leaving at least one person dead and some 40 others missing, police said.
Rescuers from the army, navy and fire department had yet to locate the bus 12 hours after the accident, DPA reported.
A female passenger was killed while at least seven others managed to swim ashore, but the fate of the remaining passengers was unknown.
Tapan Kumar, one of the survivors, said that the bus was carrying about 50 people.
Witnesses said it veered off the road while approaching the Salehpur bridge in Aminbazar, a city outskirt, before falling into the river at around 11:35 am (0535 GMT).
A 22-member team of divers from the navy and the fire service have been running underwater searches, while members of the army and police were deployed on the river banks, said Abu Nayeem Mohammd Shahidullah, head of the Fire Service and Civil Defence Department.
He said strong currents in the river have complicated the search.
Angry locals, meanwhile, blocked the Dhaka-Aricha highway complaining that authorities were delaying the rescue operation.