A gas leak in the southern port city of Karachi has killed 14 people and sickened hundreds more, Pakistani health officials said Tuesday, reports AP.

The cause of the leakage could not immediately identify. Officials said there was no suspicion of sabotage.

The apparently odorless gas, which causes severe breathing problems, has sickened hundreds since striking Karachi’s coastal neighborhood of Kamari on Sunday night when residents began rushing to local hospitals.

Hundreds of residents rallied Tuesday demanding the source of the leak be traced quickly.

Karachi is the capital of southern Sindh province, Pakistan’s largest city and the country’s chief commercial hub. It has oil refineries nearby and a key installation of Pakistan’s navy is also located there.