Dozens of survivors have been rescued from underneath large slabs of concrete in Bangladesh, as the death toll in the tragic building collapse rose to more than 247 meaning this is the worst industrial disaster Bangladesh has seen.

Rescuers found around 40 people late Thursday trapped in an air pocket in the wreckage of garment factory in Dhaka and began pulling them to safety.

More bodies were also recovered from the rubble as emergency crews struggled to find more people after muffled screams were reportedly heard from other parts of the destroyed building.

“We’ve got 247 dead but many more feared trapped under the ruins,” senior police officer Moshiuddowla Reza told AFP, adding most of the deceased were from the 3,000-strong mostly female workforce in the building’s garment factories.

Volunteers sent food and water through holes to people trapped underneath with rescuers working through the night to save them.

Wednesday’s tragedy highlights safety problems and poor working conditions that have plagued the country’s textile industry.

Survivors and police said visible cracks were seen in the eight-storey building Tuesday evening, but factory bosses had ignored police evacuation order and demanded staff return to the production lines, reports AFP.