Chinese President Xi Jinping yesterday warned against foreign influence on religious groups in China because they must pledge allegiance to the state.

"We must manage religious affairs in accordance with the law and adhere to the principle of independence to run religious groups on our own accord," President Xi Jinping said.

The leading Communist Party in China is officially atheist, and the country has long been considered one of the worst in the world for religious freedom.

It has been designated a country of particular concern regarding religious freedom by the US since 1999, and the latest report from the Commission on International Religious Freedom found an "alarming increase in systematic, egregious, and ongoing abuses" in 2014.

The President also said: "Active efforts should be made to incorporate religions into socialist society," adding that the party's religious efforts should be channelled into winning the public over to the party. His comments were made at a high-level party meeting but were widely reported in state media.

The Chinese government believes that religion is one way for foreign forces to exert influence over the population, so foreign missionary work is forbidden. It is also against the law to pledge allegiance to any foreign figure, including the Pope, which has led many Catholics and Protestants to attend underground or house churches.

Pope Francis yesterday issued a special call for the faithful to pray for Catholics in China on the feast of Our Lady, Help of Christians, celebrated on May 24.

"Ask Mary to help Catholics in China to be ever more credible witnesses of this merciful love in the midst of their people, and to live spiritually united to the rock of Peter on which the Church is built," the Pontiff said during his weekly audience in St Peter's Square.

The Vatican severed diplomatic ties with China in 1951, but the Pope expressed a desire to normalise relations during his visit to South Korea last year. There are thought to be 12 million Catholics in China.