XI'AN - Ten miners have been confirmed dead after they were trapped underground following a fire that broke out on Tuesday in a sulfur mine in Northwest China's Shaanxi province, rescuers said Wednesday.

As of 7:20 am Wednesday, seven bodies of the trapped miners have been lifted from the pit while three others in the pit have also been confirmed dead, according to rescuers.

Zhong Hongliang, a rescuer monitoring harmful gas at the head of the pit, said mist containing carbon monoxide keeps rising from the pit, which can lead to coma.

Thirty rescuers have made continuous efforts to rescue the trapped miners and they found that the concentration of the carbon monoxide in the pit has stood at about 1,000 parts per million (ppm) which can be fatal, according to Dang Li, leader of the rescue team.

A total of 27 miners were trapped in the pit when the mine, located in Chengcheng county, caught fire around 1 pm on Tuesday.

Seventeen of the miners have been rescued as of Tuesday afternoon. Nine injured miners are being treated at a local hospital and their condition is stable. Eight others appeared unscathed, said hospital sources.

Initial investigation showed that the accident was caused by a fire broke out at a cable when miners doing some repair works in the pit.