VATICAN CITY (Reuters) - The China Philharmonic Orchestra will perform for Pope Benedict next week in an unprecedented gesture that Vatican sources said could signal a thaw in often icy relations between the Vatican and Beijing.

Vatican Radio said on Tuesday the concert will take place on May 7 in the Vatican's vast audience hall. The orchestra will perform Mozart's "Requiem" along with the Shanghai Opera House Chorus.

The radio called the concert, which will take place during the orchestra's European tour, "important" and added:

"With the performance in the Vatican of a great classic opera of European music and religious inspiration, music is confirming its role as a language and most precious medium for dialogue among peoples and cultures."

Benedict has made improving relations with Beijing a major goal of his pontificate and issued a 55-page open letter in June saying he sought to restore full diplomatic ties with Beijing that were severed two years after the 1949 Communist takeover.

"This could not have happened without the government approving it," said one diplomatic source.

Catholics in China are split between those who belong to a state-backed Church and an underground Church whose members are loyal to the Vatican.

Relations between the Vatican and Beijing have hit low points several times in recent years as the Vatican criticised China for appointing bishops without papal approval.

Benedict accused China of "grave violations of religious freedom" in 2006.

Relations warmed significantly last September when the Vatican approved the installation of a new state-approved Catholic bishop of Beijing.

Last month Benedict called for dialogue to end the "suffering" of the people in Tibet and a Chinese crackdown but used extremely diplomatic language.

Beijing wants the Vatican to sever diplomatic relations with Taiwan, which China considers and renegade province.

In 2007, the Vatican did an about face over a meeting between the pope and the Dalai Lama.

A Vatican official told reporters in late October the pope had scheduled a meeting with the exiled spiritual leader of Tibetan Buddhism on Dec. 13.

Beijing responded by saying such a meeting would "hurt the feelings of the Chinese people" and urged the Pontiff to show he "is sincere in improving relations".

Later that month, the Vatican said the pope had no plans to meet the Dalai Lama during his visit to Rome, saying they had met the previous year.

By Philip Pullella Copyright © 2008 Reuters