A fire in a clothing factory in Karachi has killed more than 100 people, many of them women and children.
More than 40 fire engines tried to tackle the blaze which broke out late on Tuesday night, however the building continues to smoulder, the BBC reports.
Metal grilles blocked the factory windows on the lower floors, trapping an estimated 1,600 workers inside and leaving them with only one exit.
As the workers became desperate many tried to jump from the windows higher up, where the fire was raging intensely. Some of the people who died were killed by the injuries they sustained falling from the building.
BBC correspondant Aleem Maqbool has said it could be Pakistan's “worst fire for 10 years.”
Earlier on Tuesday a fire broke out in a shoe factory in Lahore, killing at least 25 people.
The two disasters have shone a light on government failings in Pakistan after police said both buildings had no safety regulations and did not come under inspection.
The faulty electrical generator that sparked the blaze in Lahore was installed because of the unreliable power supply in the country.
As relatives wept outside the buildings, clothing factory employee Mohammad Pervez told Reuters: "The owners were more concerned with safeguarding the garments in the factory than the workers.
"Whoever complained was fired."