SHANGHAI - The pastor of one of China's best-known unregistered "house" churches was sentenced to nine years in prison on Monday on charges of inciting subversion of state power, part of Beijing's crackdown on unregistered religious groups.Wang Yi, pastor of the Early Rain Covenant Church in the southwestern city of Chengdu, was among dozens of the church's members and leaders detained by police in December 2018, most of whom were subsequently released. China's constitution guarantees religious freedom, but since President Xi Jinping took office six years ago, the government has tightened restrictions on religions seen as a challenge to the authority of the ruling Communist Party.The government has cracked down on underground churches, both Protestant and Catholic, and has rolled out new legislation to increase oversight of religious education and practices, with harsher punishment for practices not sanctioned by authorities."Today's verdict makes a mockery of China's supposed religious freedoms," Amnesty International China researcher Patrick Poon said in a statement."Wang Yi was merely practicing his religion and peacefully standing up for human rights in China. This nine-year sentence is appalling and unjust."Chinese law requires that places of worship register and submit to government oversight, but some have declined to register, for various reasons, and are known as "house" or "underground" churches.Wang was profiled in Beijing-based journalist Ian Johnson's 2017 book The Souls of China, and was also among three Chinese Christians who traveled to Washington in 2006, where they met with then-president George W. Bush, asking for his support in their fight for religious freedom.An unusually outspoken religious figure, he has openly criticized Xi and wrote in an essay before his detention that Communist Party ideology was "morally incompatible with the Christian faith."Quotes attributed to him on a Facebook page run by the church's supporters' include one that said, "the Communist Party may kill my body but it cannot kill my soul."Wang's sentencing was announced in a brief statement on the website of the Chengdu court, which said he had been charged with illegally operating a business.Wang was also deprived of his political rights for three years and 50,000 yuan ($7,160) of his personal property was confiscated as part of his sentencing, the court said.In 2009, China sentenced Nobel Peace Prize-winning dissident Liu Xiaobo to 11 years in prison on charges of "inciting subversion of state power." Liu, a writer and activist, died in prison in 2017 after being denied permission to go abroad for treatment of late-stage liver cancer.