China's highest ranking prelate, Cardinal Joseph Zen, is urging Pope Francis not to cut a deal with the Chinese government that would undermine the sacrifice and fidelity of members of the underground Catholic Church in the country.

"We are very much worried because it seems that the Vatican is going to make a very bad agreement with China," Cardinal Zen told LifeSiteNews in an interview published Tuesday.

Zen said that Pope Francis "is really naïve" and "doesn't know the Chinese communists."

Moreover, "the people around him are not good at all. They have very wrong ideas. And I'm afraid that they may sell out our underground Church," Zen added.

In past months, the Vatican has been engaged in talks with leaders of China's Communist Party in an effort to establish diplomatic ties with the country. Critics suggest that if the deal happens, the Vatican would likely have to give up its existing ties with the government in Taiwan, which currently only has official ties with a few small, mostly poor countries.

The deal being discussed would reportedly hand over a certain amount of decision-making power to the Chinese government regarding the naming of new bishops. The government would propose candidates and the Pope would choose from among the clergy vetted by the communists.

Priests and bishops in the underground church have faced imprisonment for their fidelity to the Holy See, rather than submitting to the "patriotic" church under the control of the Communist government.

Zen, the Bishop Emeritus of Hong Kong, said that China's communist rulers want "total surrender" from the Church.

In an apparent move to placate Chinese leadership, Pope Francis recently defended the practice of religious liberty in the officially atheist country, insisting that in China churches are full and religion is freely practiced.

In a lengthy interview with the Spanish daily El País, the Pope said he would love to visit China "as soon as they invite me," something he says he has made clear to Chinese authorities.

Francis said that the Vatican is engaged in ongoing dialogue with China and that a commission has been set up that meets every three months, with Beijing and the Vatican alternating as hosts of the encounter.