Pope Benedict XVI on Wednesday urged bishops in China to remain loyal to Rome, speaking out in the latest round in the Vatican's struggle to obtain a church free of official interference.

Benedict at his weekly general audience also asked for prayers for the Chinese faithful, saying they want "unity with the universal church, with the supreme pastor, with the successor of Peter."

China and the Vatican have no formal relations and even informal contacts have recently been tense. That is largely due to Beijing's insistence that it has a right to assign bishops through carefully orchestrated elections, defying the pope's authority to make such appointments.

An accommodation in which most new bishops received tacit approval from the Vatican appeared to break down last year, with China accusing the Vatican of seeking to interfere in the rights of Chinese Catholics to practice their faith.

China says about 6 million Catholics worship in official congregations in the government-backed Patriotic church, although millions more are believed to worship in underground congregations loyal to the pope.

Benedict said he hoped through prayers that the bishops' wish to remain loyal to Rome "will prove stronger than the temptation to follow a path independent of Peter."

"We know that among our brother bishops there are some who suffer and find themselves under pressure," the pope said. " To them, to the priests and to all the Catholics who encounter difficulties in the free profession of faith, we express our closeness."