The roof of a five-storey cement factory under construction in Bangladesh has collapsed, killing at least four workers and trapping many others, an official said.
About 150 workers were on duty when the collapse occurred in Mongla in Bagerhat district, fire official Mizanur Rahman said.
He said at least 40 people were rescued from the debris and up to 40 others were feared trapped. Many of the survivors were taken to hospital.
The cause of the collapse is under investigation.
Survivors said 50 to 60 people were working on the roof while others were on the ground floor when the collapse occurred, according to local government administrator M Jahangir Alam.
It was not clear how many were directly affected by the collapse.
The seaside factory, about 85 miles south west of the capital Dhaka, is owned by an army welfare organisation, the United News of Bangladesh news agency reported.
In April 2013, a building housing garment factories collapsed in Dhaka, killing more than 1,100 people. Engineering surveys show that many Bangladesh factories violate building codes by using substandard materials or adding extra floors that the building foundations cannot support.