Authorities in China marked the Lunar New Year holiday on Jan. 28 by intensifying their persecution of Christians.

Among those hit hard by the new wave of persecution were Christians living in the autonomous Chinese region of Xinjiang where more than 80 believers were arrested and detained leading up and after the holiday, according to persecution watchdog China Aid.

They were arrested during raids conducted by government security agents on various house churches affiliated with the Protestant house church network, Fangcheng Fellowship, which has an estimated 10 million members.

The raids were conducted in the cities of Urumqi, Kuytun and in Shawan counties, the belated report said. Those arrested were charged with crimes such as "engaging in religious activities at non-religious sites," said China Aid.

Chinese authorities only allow the operation of the state-run church called the Three-Self Patriotic Movement.

Among those arrested were six women who were imprisoned for 15 days and fined the equivalent of $145 on the charge of "gathering and praying under the name of Christianity."

The detainees were officially released on Feb. 9 on the condition that they would join the state-run church, according to China Aid.

"We believe in Jesus wholeheartedly. What just happened was not fair. We did not cause trouble. We did not bother the neighbours. All we did was study the Bible," Chen Xiangyan, one of the women who were detained, was quoted as saying.

Aside from conducting church raids, Chinese authorities are also busy cracking down on foreign Christian missionaries, deporting at least 32 South Korean missionaries in February as part of the government's crackdown on evangelism.

Last week, five Christians, including a pastor, were sentenced to three to seven years in prison on charges that they bought and sold what the Chinese government considers to be "forbidden Christian devotional books."

In its 2016 Annual Persecution Report, China Aid noted that there has been a "seismic shift" in China's approach to religion, which has led to a massive rise in persecution of Christians and other faiths.

Christians are being persecuted "at a frequency unseen since the Cultural Revolution," the human rights charity says.

It says persecution cases went up by more than 20 percent last year compared to 2015, with the number of people detained increasing by nearly 150 percent.

Open Doors USA ranks China as the 39th worst country in the world when it comes to the persecution of Christians, according to its 2017 World Watch List.