Rescuers in Bangladesh searched through the wreckage of a factory on Friday, a day after it collapsed killing at least seven people.

Soldiers and sailors in the port town of Mongla helped emergency services search through rubble and pull out nearly 50 survivors as well as two more bodies overnight.

"Most of the people inside the building have been rescued alive but rescue operations are still going on until the last body is recovered," senior district official Mohammad Shah Alam Sardar said by telephone from the scene.

Soon after the accident on Thursday, police estimated that 100 people were trapped but the number was much lower, Sardar said.

"We suspect only a few more bodies will be found under the debris."

Thirty people were injured, officials said, far lower than the initial esimate.

The factory, run by a subsidiary of the Bangladesh army, collapsed in the port town of Mongla, 210 miles southwest of the capital, Dhaka.

"There were about 150 people, including workers, inside the factory building when it collapsed," said Belayet Hossain, the officer in charge of the Mongla Port police station near the factory.

Bangladesh has a poor record for building safety.

A complex of shops and small factories collapsed in 2013 killing more than 1,130 people, most of them garment workers.

The collapse of Rana Plaza, built on swampy ground outside the capital, Dhaka, ranked among the world's worst industrial accidents and sparked a global outcry for improved safety.

Reuters