A trip by Pope Benedict to China would be "unthinkable" at the moment because there is not enough religious freedom there, a Vatican official said on Wednesday.

Pope Benedict has made improving ties with Beijing a major goal of his pontificate and last year a senior figure in China's state-controlled church said he hoped the German-born Pope would make a landmark visit there.

But the Vatican official, speaking to reporters on the condition he not be named, said such a trip was impossible given current divisions among China's 8 to 12 million Catholics.

They are split between the Church approved by the ruling Communist party and an "underground" church wary of government intervention.

"If we don't arrive at a decent level of religious freedom, what can the Pope do in Beijing? Meet the president of the country? And then only see the official (state-backed) community?" the official asked.

"So, today, a trip to China is unthinkable, even if it's the desire of Pope Benedict. But today there are not the conditions for this to happen."

At the same time, the official stressed that communications were improving on both sides, and that diplomacy takes time.

Relations have hit low points several times in recent years as the Vatican criticised China for appointing bishops without papal approval. In May 2006, Pope Benedict accused China of "grave violations of religious freedom".

But last June, the Pope issued a letter to China's Catholics that urged reconciliation.

Liu Bainian, vice-chairman of the Chinese Catholic Patriotic Association, which often speaks for the state-controlled body, responded the next month by calling the Pope's letter "a big step forward" in an interview with an Italian newspaper.

He said he hoped "with all of my strength" to be able to see Pope Benedict some day celebrating mass in China.

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