RUPGANJ, (Bangladesh): A massive blaze tore through a Bangladesh factory killing at least 52 people trapped by flames that forced workers to leap for their lives from upper floors, emergency services said on Friday.

About 30 people were injured in the fire, and hundreds of distraught relatives and other workers waited anxiously outside the food factory as it continued to rage.

The inferno was the latest to tarnish Bangladesh's safety record marred by a series of disasters in industrial complexes and apartment buildings.

The country has pledged reforms since the Rana Plaza disaster in 2013 when a nine-storey complex collapsed killing more than 1,100 people. But critics say safety standards are still lax.

In February 2019 at least 70 people died when an inferno ripped through Dhaka apartments where chemicals were illegally stored.

The latest fire broke out at Hashem Food and Beverage factory in Rupganj, an industrial town outside Dhaka, on Thursday afternoon and was still raging almost 24 hours later.

Normally there were would be more than 1,000 workers in the building but many had left for the day when the fire started.

The overnight toll of three dead rose dramatically as firefighters reached the third floor and found 49 more bodies. Fire service spokesman Debashish Bardhan said: "The workers could not go to the rooftop because the exit door to the staircase was padlocked. They could not go down because the lower floors were already engulfed by fire." The charred victims were piled into a fleet of ambulances to take them to mortuaries amid anguished shouts and tears from people watching in the streets.

Police dispersed hundreds of people who blocked nearby roads, while some clashed with officers.