Islamabad: At least four workers were killed after a huge fire broke out in an oil depot in Pakistan's Faisalabad city, officials said on Tuesday.

The bodies of the workers killed in the blaze were retrieved, while four others were shifted to a local hospital with severe burn injuries, reports The Express Tribune.

Rescue teams and 16 fire engines reached the site of the incident on Abbaspur Road in Sudhar area to extinguish the fire.

The blaze that erupted on Monday night engulfed the oil drums in different parts of the depot with the workers trapped on the premises.

Over 30 employees were working at the place and 25 of them were rescued safely.

District Emergency Officer (DEO) Ahtisham Wahla said the oil depot was operating illegally.

"Neither the district administration nor police were aware of this depot working in the area. There were no safety measures in place at the depot to protect the property and the workers from an accident," The Express Tribune quoted the DEO as saying.

The depot was situated away from the populated area of the city.

The cause of the fire has not been determined yet.