China has banned retired Communist Party members from believing in a religion or practicing religious activities, BBC News reports citing state media.

China is officially atheist but says it guarantees religious freedom. However, serving Communist Party members are not expected to be religious.

Newly published Party rules now say retired officials are also barred from religion and must oppose cults, state media said.

The regulations were issued by the Communist Party's powerful Organization Department.

Chinese media quoted an official, explaining the new regulations, as saying: "There are clear rules that retired cadres and party members cannot believe in religion, cannot take part in religious activities, and must resolutely fight against cults."

Retired officials should "maintain a high degree of consistency, in thought, in political views and in action, with the central party committee which is headed by Xi Jinping", the official added.

China's constitution guarantees religious freedom, but in practice religious activities are tightly controlled.

All churches have to be approved by the state and authorities keep a close eye on their activities to contain their influence.

Muslims in Xinjiang have also faced restrictions on their religious activities, while the Falun Gong spiritual movement has been denounced as an "evil cult" and has been banned since 1999.