BEIJING/ROME - The Vatican on Tuesday condemned the appointment of a Chinese Catholic bishop without its approval, hours after a source said one of Rome's own newly-ordained bishops had been detained in a seminary in China.

In a move likely to strain already frayed relations with Beijing, the Vatican said it refused to recognize the ordination on July 6 of Reverend Joseph Yue Fusheng in Harbin, complaining his elevation by Beijing's state-run Church overseer had not been blessed by the pope and was therefore meaningless.

"All Catholics in China, pastors, priests, consecrated persons and lay faithful, are called to defend and safeguard that which pertains to the doctrine and tradition of the Church," the Vatican said in a statement.

Branding the act illicit, it said such unsanctioned appointments "cause division and bring suffering to the Catholic communities in China and the universal Church".

Any bishops who took part in the ordination would have to explain themselves, it added.

The statement was an escalation in a long-running dispute over the status of China's state-backed church, which rejects papal control. Beijing and the Vatican differ over who has the authority to appoint bishops.

The spat came as Beijing and the Vatican were squaring off over another ordination - this time one that the pope blessed - which took place in Shanghai on Saturday.

A source close to the Vatican told Reuters on Tuesday that the cleric at the centre of that dispute, Thaddeus Ma Daqin, had been taken away by officials and held in his seminary.

DETAINED BISHOP

On his ordination as auxiliary bishop of Shanghai, Ma publicly quit his posts in the state-run Catholic Patriotic Association, which oversees the church in China but which is not recognized by the Vatican.

In its statement on Tuesday, the Vatican made no mention of Ma's apparent troubles, saying only that his ordination was "encouraging", while complaining about the presence at the ceremony of a bishop nominated by the Chinese church.

The Reuters source, who declined to be named citing the sensitivity of the matter, said China often restricts the movements of Vatican-approved bishops.

The source said Ma, who is now in the Sheshan seminary in Shanghai, had failed to appear in Sunday to celebrate Mass. Calls to the seminary went unanswered.

Repeated calls to the Chinese Catholic Patriotic Association went unanswered too.

Chinese Catholics number between 8-12 million, and are divided between a state-sanctioned church that has installed bishops without Vatican approval and an "underground" wing long wary of associating with the Communist Party-run church.

China and the Vatican broke off formal diplomatic relations shortly after the Chinese Communists took power in 1949. Pope Benedict has, however, encouraged the two sides of the divided Chinese church to reconcile, and engaged in a low-key dialogue with Beijing about political ties.

The Vatican has previously condemned what it called "external pressures and constrictions" on Catholics in China.

(Reporting By Naomi O'Leary; Editing by Andrew Osborn)