At least 246 people have died in a fire at a garment factory in Karachi, officials say, in one of Pakistan's worst ever industrial accidents.
Many others were injured in the inferno which raged for 15 hours overnight.
Hundreds were trapped inside - the building had metal grilles on the windows and no fire exits.
Many workers jumped from the upper floors.
Some 40 firefighting vehicles were needed to tackle the blaze.
Rescuers have spent the day recovering bodies.
There are reports of people trapped inside frantically ringing their friends and relatives as flames engulfed the building.
The fire broke out hours after another blaze at a shoe factory in Lahore killed at least 25 people.
Investigations have been announced into both fires.
Reports say they may have been caused by faulty electricity generators.
In Karachi, the building was still smouldering on Wednesday as rescuers pulled out the bodies of those who had been trapped inside.
Provincial Health Minister Sagheer Ahmad said the number of dead had now risen to 246.
"These are not the exact figures as rescue work is still ongoing," he told reporters.
Karachi fire Chief Ehtesham Salim said: "We found people who died because of suffocation caused by the highly toxic smoke.
They died first and then their bodies were burned by the raging fire."
Workers had little time to escape from the four-storey building's single exit - many could do so only by jumping from the windows.
At least 65 employees are reported to have suffered from broken bones.
"People started screaming for their lives," one survivor, Mohammad Asif, told Reuters news agency.
"Everyone came to the window.
I jumped from the third floor."
As the full horror of the blaze unfolded, shouting and sobbing relatives of trapped workers scuffled with police while rescuers battled to gain access to the roof and the basement.
Workers spoke of panic and confusion as the fire spread.
"It was terrible, suddenly the entire floor filled with fire and smoke and the heat was so intense that we rushed towards the windows, broke its steel grille and glass and jumped out," Mohammad Saleem told AFP news agency in hospital.
"I fell on the ground and it was extremely painful, I saw many people jumping out of windows and crying in pain for help."
Speaking at the scene, Karachi official Mohammad Hussain Syed said that the scale and severity of the fire made it difficult to find and identify the dead
"Some bodies are completely charred and cannot be recognised," he said.
"It is only possible [to identify them] through DNA tests.
It was a big garment factory where lots of people were working.
That's why it is difficult to assess how many have come out safely and how many failed to escape and were trapped."
Bodies have been taken to several different hospitals, and police are still compiling a definitive list of casualties.
Police said that they feared more bodies could be inside the building.
Firefighters said that the poorly ventilated factory had no fire exits or alternative means of escape and that most of the dead had been suffocated by toxic smoke.
Officials said windows at the factory were blocked with metal grilles and that it was crammed with combustible materials including piles of clothes and chemicals.
Firefighters on crane lifts have been trying to reach through windows of the gutted building to rescue trapped survivors suffering from burns and smoke inhalation.
The cause of the blaze was still being investigated, police said, but workers say it may have been caused by a faulty generator.
Garments factories across Pakistan require their own power sources because of increasingly erratic national grid electricity supplies.
The industry is critical to Pakistan's frail economy - according to central bank data, it provided 7.4% of Pakistan's GDP in 2011 and employed 38% of the manufacturing sector workforce, accounting for 55.6% of total exports.