BEIJING (AP) — A collapse occurred in an illegal mining operation in China on Sunday, killing five people and injuring one other person, Chinese official news agency Xinhua reported.

The incident took place in Huize County in Yunnan province in southwest China at about 4:30 a.m., Xinhua reported. The news outlet did not specify what kind of mine it was.

Rescuers pulled out all six people trapped at the site in Baiwu village and sent them to the hospital, but five of them succumbed to their injuries. The survivor was in stable condition, the report said.

Authorities were investigating the cause of the collapse.

Just more than a week ago, the country was hit by its deadliest coal mine explosion in recent years, which killed at least 82 people in China’s northern Shanxi province. Local officials earlier said there were “serious violations” of the law by that mine’s operator.