Leaders of Vietnam’s most active archdiocese have urged local Catholics to follow church instructions on worship and avoid deviant ritual practices claimed to caste out evil spirits.

Bishop Joseph Do Manh Hung, apostolic administrator of Ho Chi Minh City Archdiocese in the communist nation’s south, and Auxiliary Bishop Louis Nguyen Anh Tuan, said some local Catholics have adopted unsuitable practices. They warned people against Mother Mary’s Message, a Marian devotion movement launched by a lay man named Thomas Mary Nguyen Thanh Viet. It has been claimed that Mother Mary healed him of illnesses in 2010.