Chinese police have released a key 'underground' bishop after arresting him and holding him for a day as Beijing and the Vatican prepare to seal a historic agreement on the appointment of prelates, a source told AFP today.

Vincent Guo Xijin, bishop of the diocese of Mindong in the southeastern province of Fujian, was at the centre of the highly controversial deal after being urged by the Vatican to step aside for another bishop recognised by China's Communist government.

According to Asia News, bishop Gua and the chancellor of the diocese, Fr Xu, were arrested by the police on Monday evening. The status of the second church official is unclear, AFP said.

Reports said that at 3pm, bishop Guo, 59, was called into the office for religious affairs where he met with government officials for over two hours. At 7pm he reportedly returned to his residence but at 10pm he was taken away.

Beijing and the Vatican severed diplomatic relations in 1951 and though ties have improved as China's Catholic population grows, they have remained at odds over the appointment of bishops.

There are around 12 million Catholics in China who are divided between a government-run association, whose clergy are chosen by the Communist Party, and an unofficial church which swears allegiance to the Vatican.

AFP pointed out that the situation is complex because the Vatican has previously accepted several bishops appointed by Beijing, which is an officially atheist regime.

Guo, who is recognised by the Vatican but not by the Chinese authorities, was recently urged by the Vatican to step aside for Bishop Vincent Zhan Silu and to accept being demoted to auxiliary bishop, as part of preparations for the agreement.

According to Catholics consulted by AsiaNews, the disappearance of the bishop of Mindong is down to the fact that he refused to celebrate Easter with the prelate who will replace him.

According to La Croix, a Chinese delegation is expected in Rome this week.

LifesiteNews.com reported that last year, Bishop Guo disappeared at the hands of Chinese police just before Easter and reappeared 20 days later.

The website said that representatives of the underground Church say Bishop Guo was taken away for having refused to concelebrate the Easter liturgies with Bishop Zhan Silu, an illegitimate and excommunicated bishop who was approved by the Chinese authorities.