CHENGDU, March 27 (Xinhua) -- Nine people were killed and one was missing in a construction site accident on Thursday in China's southwest Sichuan Province.

    The accident occurred at about 3 a.m. at the Shawan hydropower station construction site in Muli County, Liangshan Yi Ethnic Prefecture.

    A preliminary investigation revealed all the victims, who were working in a tunnel at the time of the accident, were poisoned by a type of gas that has yet to be identified.

    The victims were employed by a construction company based in Chengdu, the provincial capital.

    An investigation is currently underway.