LANZHOU: Seven miners were killed by a poisonous gas leak in Gansu province on Friday, work safety authorities said.

The incident happened at around 5:40 pm in Baiyin city's Fengyuanshun mine, where 11 workers had been underground at the time, said Liu Tianming, director of the Gansu coal mine safety administration.

Six miners escaped but five others and two rescuers - a mine boss and a technician - were killed.