Beijing, May 23 -- A gas explosion at a coal mine in northern China has killed at least 90 people, according to state broadcaster reports, with dozens more injured and a small number still unaccounted for.

The incident occurred late Friday night at the Liushenyu coal mine near Changzhi City in Shanxi Province, when approximately 247 miners were working underground.

According to the Xinhua News Agency, the blast is believed to have been triggered by dangerous levels of carbon monoxide, which had reportedly exceeded safety thresholds inside the mine. Rescue officials said nine workers were still trapped underground as of Saturday afternoon, while intensive search-and-rescue operations continue.

State broadcaster China Central Television re...