The death toll may increase further as the rescue operation is still underway, officials said.
The fire broke out in the evening in a scrap shop on the ground floor of the building in Residency Road area apparently due to a short circuit. Soon the flames engulfed the entire building and some of the LPG cylinders kept inside exploded, said Senior Superintendent of Police, Jammu, Chandan Kohli.
He said three people, including a child, were charred to death in the incident and 15 others were rescued and rushed to the hospital.
Another body was recovered later. Residents of the building were mostly workers from Assam, the officials said.
A spokesperson of the Fire and Emergency Services Department said they received a call about the fire around 6.10 pm and immediately rushed fire tenders to the spot.
Additional Director General of Police, Jammu, Mukesh Singh also rushed to the scene to supervise the firefighting and rescue operation.
“Over a dozen families were living in the building. The fire spread very fast, many of the residents could not escape immediately,” said a building resident Anwar Hussain.
Another survivor, Yasmeena Khatoon, said the building residents lost everything in the fire.
“We could not retrieve anything and tried to flee the raging fire,” she said, adding that many of her relatives are either injured or missing after the incident.