A person died and three fell unconscious from inhaling of smoke after a fire broke out in the basement of a well-known departmental store near Jail Chowrangi in Karachi on Wednesday, police said.

Station House Officer (SHO) Arshad Janjua of Ferozabad Police Station said the deceased was an employee of the store, while among the three who lost consciousness was a firefighter.

Earlier, a fire brigade official said that around 11:15am, they received information about a fire erupting in the basement of Chase Up — the departmental store.

Footage from the scene showed plumes of smoke rising from the multi-storey building as officials tried to put out the flames. Thick smoke also engulfed the surrounding area, causing breathing problems for residents and passers-by.

A spokesperson for Sindh Rangers said paramilitary personnel had cordoned off the area and contributed to rescue efforts.

The Edhi Foundation spokesperson said that the injured and the deceased had been shifted to Jinnah Hospital.

Initially, fire tenders from the nearby Civic Centre were rushed to the scene. However, more tenders were called in from across the city once officials realised the gravity of the situation.

Karachi Metropolitan Corporation’s (KMC) Chief Fire Officer Mubeen Ahmed said 11 fire tenders belonging to the corporation, two water bowsers, one snorkel, 13 water tankers from the Karachi Water and Sewerage Board as well as tenders from the Pakistan Navy took part in dousing of the flames.

They had managed to control 70 per cent of the blaze until evening, he said. "However, officials are facing extreme difficulty as the fire erupted in the basement," he said, adding that there were no entry or exit routes.

"We are trying to control the blaze by demolishing the walls of the basement in order to access it," he said. He also lamented the fact that no thought was given to fire safety at the time of constructing the multi-storey building.

The official was of the opinion that the goods and materials stored in the basement helped the fire spread rapidly. He said the exact cause of the fire was unknown.

According to the SHO, the blaze had somewhat subsided but erupted once again at around 6pm, prompting authorities to call fire tenders to the site.

"The fire erupted again because of some unknown reasons and spread rapidly, and the firefighters are struggling to extinguish it," the officer added.

It was the first fire incident at the newly constructed building, Ahmed said, expressing concern that such incidents in the future could damage its structure.

The chief fire officer said that they would also assess the extent to which the building's structure was damaged by the fire.

Speaking to the media earlier in the day, Karachi Administrator Murtaza Wahab said that officials were focusing on damage control and dousing of the flames, adding that they would ascertain the cause once it was completed.

However, when asked whether the store had followed fire safety SOPs, Murtaza refused to comment, saying that doing so at this time would be "inappropriate".

"I have asked the Sindh Building Control Authority to dig up the map [of the building]. We will properly investigate it. Our target right now is not to affix blame, but to minimise the damage," he said, adding that the residents of the building had been evacuated.