Police have detained dozens of churchgoers and leaders of one of China's most prominent Protestant "house" churches, congregation members and activists said, in the latest government action against unregistered religious groups.

Teams of police and state security officials in the southwestern city of Chengdu came to the homes of leaders and members of the Early Rain Covenant Church late Sunday and detained them, according to church announcements sent to members and passed to Reuters by churchgoers and activists.

"The time has come. O, Lord! Did you not establish this church for this very purpose?" the church said in one of its announcements.