The Vatican on Thursday denounced new arrests of Catholic bishops in China and accused Beijing authorities of mounting "obstacles" to having a dialogue with the Holy See. The Vatican press office issued the complaint at the close of an annual Vatican meeting that is studying the problems of the Catholic Church in China. Pope Benedict XVI has made improving often tense relations with Beijing a priority of his papacy. In China, worship is allowed only in state-backed churches. Millions of Chinese, however, belong to unofficial congregations that are loyal to Rome. In 2007, Benedict sent a special letter to Catholics in China, praising the underground church but also urging the faithful to reconcile with followers of the official church. In Thursday's statement, the Vatican denounced the new arrest of the bishop of Zhengding, Monsignor Giulio Jia Zhiguo, and lamented that other priests had been detained or subjected to "undeserved pressures" by government authorities.