Hong Kong's firebrand Cardinal Joseph Zen warned Wednesday the Vatican would abandon official ties with Taiwan after sealing a historic accord with China.
Zen, the former Bishop of Hong Kong, is well-known for his vocal opposition to political suppression and his support for democratic reform.
He has consistently spoken out against any agreement between the Catholic Church and China, saying it would be a betrayal of the persecuted unofficial church on the mainland.
Zen said the new deal, announced Saturday, indicates the Vatican is willing to break ties with Taiwan, its only ally in Europe.
"The Holy See, the Vatican, is ready to abandon Taiwan," he told reporters at a press conference at the Salesian House of Studies, a training school for clergy, where Zen lives.
"I'm afraid the people in Taiwan may not understand because it looks like a betrayal of a friend."
Beijing demands any country that has relations with China must forfeit recognition of self-ruling Taiwan, which it sees as part of its territory to be reunified.
Taiwan officials say the Vatican has assured them the agreement will not affect diplomatic ties as Beijing makes a concerted effort to poach their dwindling allies.
Zen added the deal had also caused "spiritual suffering" in China's underground church.
"They fear that the Holy See is betraying the faith and that they want them to join this betrayal," he said.
The landmark accord centres on the appointment of bishops in China in what could pave the way for the normalisation of ties between the Catholic Church and the world's most populous country.
China's roughly 12 million Catholics are divided between a state-run association whose clergy are chosen by the government and an unofficial church which swears allegiance to the pope.
The Chinese Communist Party is officially atheist and religious groups are tightly controlled by the state.
Churches have been destroyed in some Chinese regions in recent months, and there has been a clampdown on Bible sales. Crosses have been removed from church tops, printed religious materials and holy items confiscated, and church-run kindergartens closed.
"In a situation of increased repression of religion, how can you think you have a good deal with them?" Zen asked.
Soon after the deal was announced, Pope Francis recognised seven bishops who had been ordained in China without the Vatican's approval.
The pope said Tuesday he would have the last word on naming bishops, but admitted members of the underground church would suffer because of the deal.
Beijing and the Vatican severed diplomatic relations in 1951 and although ties had improved as China's Catholic population grows, they had remained at odds over the designation of bishops.