No to Christian missionaries, but yes to local churches — but only under strict government control.

China has once again underscored this policy following the arrest of four South Korean Christian missionaries and the expulsion of at least 32 others last week, reports said.

The arrests and expulsions reportedly came after a series of police raids on churches as part of an ongoing crackdown against Christian missionaries, according to UCAN.

Prior to their arrest and deportation, the South Korean missionaries were reportedly conducting evangelisation activities in China's northeast Yanji region while at the same time helping North Korean defectors in navigating the risky journey across the Yalu River, which separates China and North Korea.

The South Korean government has confirmed reports that a number of South Korean missionaries had been arrested in China, according to Breibart. It noted that some of the missionaries had been working in China for decades.

Last September, Chinese authorities arrested the Vatican-appointed coadjutor bishop of Wenzhou, Msgr. Peter Shao Zhumin, on the ground that he hadn't been approved by Chinese officials, The Christian Post reported.

Bob Fu, founder and president of China Aid, an organisation that documents persecution of Christians in China, earlier provided an explanation behind China's crackdown on missionaries. Speaking to The Christian Post, he said "the top leadership is increasingly worried about the rapid growth of Christian faith and their public presence, and their social influence. It is a political fear for the Communist Party, as the number of Christians in the country far outnumber the members of the Party."

However, despite Beijing's action, Pope Francis has publicly defended China's practice of religious liberty.

Last month, in an interview with the Spanish daily El País, the pope said Christianity is thriving in China, noting that churches are full and religion is practiced freely.

He even said he would love to visit China "as soon as they invite me," according to Breitbart.

However, religious freedom groups have pointed out that religious practice in China is not free at all.

This year, the non-profit group Open Doors has placed China among the worst offenders against religious freedom in the world, ranking 39th in its 2017 "Watch List" of top Christian persecuting countries.