At least 13 people were killed and dozens were feared missing after a flyover under construction collapsed in Bangladesh's southeastern port city of Chittagong.
Sub-inspector Mohammad Alauddin said military rescue teams had been called in to help with the search for victims.
The number of missing could not be confirmed, but a police constable said dozens could be trapped under the debris.
Witnesses said more than 50 construction workers and vegetable hawkers had gathered near a pond under the bridge at the end of work when three concrete girders crashed down.
"Instantly the whole area was covered by smoke and dust," Syed Mainuddin, a witness, said.
At least 15 people were rescued and taken to hospital.