More than 200 people are now known to have died in a fire at a garment factory in Karachi, Pakistani police have said.
Many others were injured in the blaze. It began on Tuesday night, hours after a factory fire killed 23 in Lahore.
Correspondents say that the Karachi blaze is one of the worst industrial accidents in the country’s history.
Some 40 firefighting vehicles were needed to tackle it, officials said. Rescuers are still recovering bodies.
The cause of both fires are being investigated. Reports say that both may have been caused by faulty electricity generators.
Medical officials said victims in both fires mostly died of suffocation, while others were burned alive as the infernos took hold.
In Karachi, the building was still smouldering on Wednesday as rescuers pulled out the bodies of those who were killed. Officials said the number of dead had now risen to 212.
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 – many could do so only by jumping from the windows. At least 65 employees are reported to have suffered from broken bones.
As the full horror of the blaze unfolded overnight, shouting and sobbing relatives of trapped workers scuffled with police as rescuers battled to save people still thought to be trapped in the building.
Chief Fire Officer Ehtishamud Deen said that his staff was trying to rescue about 20 people trapped in the basement and on the fourth floor.
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 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,” he said.
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 recognized,” 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.”
“The condition of the building is very bad now.”
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 are now trying to reach through windows of the gutted building to rescue trapped survivors, all suffering from burns and smoke inhalation.
The cause of the blaze was still being investigated, police said, but workers say it too 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.