VATICAN CITY (AP) — A Catholic missionary news agency says an underground Chinese bishop who is a key player in a proposed Vatican-China deal over bishop nominations has been released.

AsiaNews says Mindong Bishop Vincenzo Guo Xijin was taken into police custody to prevent him from celebrating a Holy Week Mass. He was released Tuesday after a night in detention.

His removal came as the Vatican seeks to sign a deal with Beijing that would regularize relations between China’s underground and state-controlled Catholic churches, by having the Vatican recognize seven bishops not chosen by the pope and having Guo step aside.

Lu Kang, a Chinese foreign ministry spokesman, said he didn’t have any information about Guo’s detention but said the Chinese people enjoy religious freedom. Lu also said Beijing has worked hard to improve relations with the Vatican.