The U.S. has called for the release of 30 leaders of one of China's largest underground church networks who were reportedly detained over the weekend in overnight raids in various cities.

The list includes several pastors and Zion Church founder Jin Mingri who was arrested in the early hours of Saturday after 10 officers searched his home, according to U.S.-based non-profit ChinaAid.

The Chinese Communist Party promotes atheism and tightly controls religion, yet some Christian groups are claiming this marks the most extensive crackdown against the faith in decades.

Christians have long faced pressure to join only state-sanctioned churches led by government-approved pastors who align with the party's ideology.

It remains unclear if the detainees have been formally charged. Zion Church responded to the detentions, stating that such systematic persecution is not only an affront to the Church of God but also a public challenge to the international community. U.S. Secretary of State Marco Rubio urged China to release the church leaders, emphasizing that the crackdown further shows the CCP's hostility toward Christians who refuse to allow Party interference in their faith.

Former U.S. officials, including Mike Pence and Mike Pompeo, also condemned the arrests through social media statements.

Chinese foreign ministry spokesperson Lin Jian stated he was unaware of the case and defended the government's actions. He emphasized that China manages religious affairs per the law and protects the religious freedom of its citizens.

This situation may contribute to escalating tensions in U.S.-China relations, especially amid ongoing trade disputes. Under Xi Jinping's leadership, the Chinese government has intensified its crackdown on religious freedom, particularly against Christians and Muslims.

Despite the risks, there is a burgeoning movement of unregistered house churches in China, including the Zion Church, founded by Mr. Jin in 2007. This church now boasts a network of 10,000 followers across 40 cities.

The Party officially banned Zion Church in September 2018 after it refused government demands to install surveillance cameras in its facilities. Church leaders have faced previous detentions, and Mr. Jin's family relocated to the U.S. for safety while he remains to lead his congregation.

With recent detained church leaders potentially qualifying this as the largest coordinated persecution of Christians in over 40 years, comments from ChinaAid's Bob Fu resonate with the historical context of the 1980s when church activities faced severe repression.

Mr. Jin's wife expressed her despair over the detentions, noting the heartbreak and concern for her family, while other house churches have echoed calls for the detainees' release.

Sean Long, a Zion Church pastor in the U.S., indicated that Mr. Jin anticipated possible crackdowns, indicating a resolve within their community regardless of governmental oppression.