At least 16 workers died and more were missing after a factory fire in Pakistan's commercial capital Karachi on Friday, police said. 

The fire broke out at a multi-story chemical factory in the eastern part of the city, and most windows of the factory were blocked, fire officials told Reuters. 

More than 25 laborers were inside the small factory in a residential area of the port city when the blaze broke out, causing it to fill with thick smoke.

Many factory workers died after being trapped on the second floor in the fire, which broke out on the ground floor of the three-story building.

"We have recovered 16 bodies so far," senior police officer Shahjehan Khan told AFP, adding that the factory had no proper fire exits. "We are trying to recover more stranded people but I fear they might not make it out."

"The factory had only one entry point, which was also being used as exit, and the roof exit was blocked, which badly hampered rescue efforts," Mubeen Ahmed, chief fire officer of the fire department, told a television outlet.

(With input from Reuters, AFP)