Drone footage shows towering flames engulfing the factory as thick smoke rises across the area. Firefighters are seen directing water hoses at the blaze while residents gather nearby.

The fire is believed to have started shortly after midnight at the factory on Jalan Pondok Kelapa Selatan.

"Suddenly, there was what sounded like an explosion, and then the fire suddenly grew bigger," recalled a local. "The area behind it (the factory) is densely populated, so residents immediately tried to evacuate themselves and save their valuables."

A local security officer also recalled hearing an explosion as the fire spread.

"I heard that it may have started from burning rubbish. Not long after that, the fire grew bigger, and there was a sound of an explosion. It wasn’t very loud, just a small one," the officer said.

Around 100 personnel and 22 fire department units were deployed to fight the blaze and prevent it from spreading through the densely populated area, according to local media .

Firefighters reportedly struggled to find nearby water supplies. Narrow access routes through the surrounding neighbourhood also made it difficult for crews to reach the fire.

The firefighting operation was still underway at the time of publication. Authorities had yet to determine the cause of the fire or confirm whether anyone had been killed or injured.