KARACHI: Police in Karachi have registered a murder case against the owners of a garment factory where a fire killed at least 258 people in the country's worst ever industrial disaster, officers said on Thursday.

The government has ordered an inquiry and a senior official already told AFP that the two brothers who owned the factory have been barred from leaving the country.

A case has been filed against Abdul Aziz, Mohammad Arshad and Shahid Bhaila and other members of the management of Ali Enterprises, Mohammad Nawaz Gondal, the head of the local police station, told AFP.

“We have registered a murder case against the owners of the factory and several government officials for showing utter negligence to provide adequate security to the factory workers, which resulted in the deaths of hundreds of people,” Gondal said.

A senior Karachi police officer, Naeem Akram, confirmed the move.

Police are hunting for the factory owners, who have not been seen since the blaze, which erupted late on Tuesday.

The government of Sindh province, of which Karachi is capital, has appointed a retired judge to lead an investigation into the fire, with initial findings expected in a week.

The probe will look into the cause of the fire, protection systems available inside the building and the extent of negligence on the owners' part, a provincial government statement said.

Workers were suffocated or burnt alive at the Ali Enterprises garment factory in Karachi, which made ready-to-wear clothing for Western export, when a massive fire tore through the building during the evening shift on Tuesday.

Up to 600 people were working inside at the time, in a building that officials said was in poor condition without emergency exits, forcing dozens to jump from upper storeys to escape the flames, but trapping dozens in the basement where they perished.

Karachi, Pakistan's biggest city with a population of 18 million, shut down in mourning on Thursday for the deaths.

Public transport was suspended and schools and colleges closed. Factories and markets also shut while attendance at offices was thin.

Relatives spent a second day at hospitals, desperate for news of their loved ones, breaking into wails and sobs when medics confirmed the identity of yet another body.

With so many burnt beyond recognition, only 140 of the dead had been identified by Thursday morning, some by DNA, and 115 bodies handed back to families for burial, city police chief Iqbal Mehmood told AFP.

Even 36 hours after the disaster began, several families still gathered outside the gutted factory hoping for news of their loved ones.

Just a few fire tenders were still working.

There was thick smoke in the basement and it was still too hot to go inside, where boiling water formed a pool after firefighters spent hours hosing the flaming building.

“The place is too hot and smoky, it is too risky to go inside and clear the building. We are waiting for now,” chief fire officer Ehtesham Salim told AFP.

Ambulances continued to ply back and forth to the factory, even as funeral prayers for some of the dead had already begun.