The sources, who spoke on condition that they not be named, said the Vatican realised that China is trying to improve its international image but that Church officials hope the performance could be a seed for eventual diplomatic relations.

However they cautioned not to expect any immediate breakthroughs following Wednesday night's concert at the Vatican.

"I don't think they (the communist government) are doing it out of love for the pope or love of the Holy See but it will be positive in the end," said one source, a priest who is familiar with the situation.

The orchestra, currently on a European tour, will perform Mozart's "Requiem" and Chinese folk songs along with the Shanghai Opera House Chorus in the Vatican audience hall.

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 China that were severed two years after the 1949 Communist takeover.

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.

The priest said a Chinese diplomatic envoy approached a Vatican official outside Italy and made the offer. An initial offer for the orchestra to play for the pope was made several months ago but the concert could not be arranged.

"It's very important that they made the offer again," the priest said. "It will be positive for the Chinese people to see the pope too," adding that he expected the concert to be broadcast on Chinese television.

GOOD WILL HUNTING

Another source said the Chinese were clearly "shopping for good will" in an effort to improve China's international image, tarnished by recent unrest in Tibet and disruptions of the international leg of the Olympic torch relay.

"Each side clearly has its own interest in this," the second source said, calling the Vatican's willingness to host the concert "a good will gesture".

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.

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

In Beijing, conductor Yu Long saw parallels between the performance and the New York Philharmonic's ice-breaking concert in Pyongyang, North Korea in February.

In both cases, orchestras were being used to set the mood music for diplomatic warming.

"You can make that comparison. If music as a universal language can make a contribution to diplomacy or world peace, I will be very happy," Yu told Reuters in an interview.