The Vatican said on Monday expressed "grave concern" over the fate of a Chinese bishop arrested in May, Peter Shao Zhumin.
"The Holy See is observing with grave concern the personal situation of Bishop Peter Shao Zhumin of Wenzhou, forcibly removed from his episcopal see some time ago," the Vatican said in a statement.
The diocese of Wenzhou in southeast China, the local Catholic community and the bishop's relatives have received no information on Shao's health, whereabouts or the reasons for his removal, the Vatican said.
"The Holy See is profoundly saddened for this and other similar episodes that unfortunately do not facilitate ways of understanding," it stated.
China does not recognise Shao's appointment and its Communist authorities have been at loggerheads with the Vatican for decades over its insistence that only the Pope can appoint bishops.
Shao's elderly mother fears he will be returned to her in a body bag after being tortured and left to die, journalist and Vatican watcher Sandro Magister wrote last Thursday in his blog published on Italian weekly L'Espresso's website.
This was the grim fate met by John Gao Kexian, bishop of Yantai, in 2004, and by John Han Dingxian, bishop of Yongnian, in 2007, Magister noted.
Shao's disappearance is believed to be part of an attempt to persuade him to join the Communist-controlled Chinese Catholic Patriotic Association church, according to a report last week by a Vatican-linked missionary news service.
Other Chinese bishops have been arrested for not wanted to join the Catholic Patriotic Association church or for dissociating themselves from it - Mindong bishop Vincent Guo Xijin was detained during Lent this year and the bishop of Shanghai, Thaddeus Ma Daqin, in 2012, Magister reported.