Nine more people were arrested on Friday in connection with the deaths of 21 miners in a flood at a pit in southwest China's Yunnan Province, local authorities said Saturday.

Those arrested included the coal mine's board chairman Zhang Kexiang, general manager Shen Youming, and legal representative Li Xiaosheng, said the Qilin district people's procuratorate in Qujing City.

It said the nine were arrested for breaking work safety rules, causing a serious accident with casualties.

Up to now, 11 people including two local work safety officials have been arrested.

A flood occurred in Xiahaizi mine in Qujing on April 7, which led to 21 deaths. One person remains missing. The mine was operating illegally at the time.