ROME – In a sharp escalation of tensions between China and the Vatican, Pope Benedict XVI on Thursday repudiated the unauthorized appointment of two Chinese bishops and indicated they and the two prelates who ordained them could be excommunicated.

The actions by China’s state-sanctioned church, and the scathing reactions here, undermined what had been a prolonged period of rapprochement between Beijing and the Vatican.

It also marked the most dramatic diplomatic moment yet for Benedict’s year-old papacy.

The pope learned with “profound displeasure” of the ordinations in China earlier this week, Vatican spokesman Joaquin Navarro-Valls said in an unusually tough statement. He said the consecrations represented a “grave violation of religious freedom” that has done serious harm to the unity of the Roman Catholic Church.

Navarro-Valls termed the unauthorized appointments “unacceptable acts of violence and inadmissible coercion.” The so-called “patriotic” Catholic Church in China named as bishops Ma Yinglin in the southern city of Kunming on Sunday and Liu Xinhong in central Wuhu on Wednesday, neither with Vatican approval.

Authority over the appointment of bishops has long remained a matter of great dispute in this religious power struggle.

Navarro-Valls said the two priests, as well as the two bishops who consecrated them, are subject to a provision of canon law that requires automatic excommunication in cases of ordination performed without papal consent, a severe and rarely enacted punishment.

However, the statement also noted that priests in China operate under “strong pressures and threats,” a possible mitigating circumstance when excommunication is being considered. A final decision on disciplinary steps had not been taken.

Still, the controversy marked a significant setback in recent efforts to improve Sino-Vatican relations. China and the Vatican cut ties in 1951, soon after the Communist Party came to power; the Asian giant’s 10 million to 12 million Catholics are divided between the official church approved by the ruling party and an underground church loyal to Rome.