US envoy for religious freedom Sam Brownback defended his remark that China is "at war with faith" after the Chinese foreign ministry issued an angry statement condemning the envoy's words as a "malicious attack and slander on China's religious policies".
Brownback criticised the Chinese government in a speech on Friday in Hong Kong, saying the Chinese government is engaged in the persecution of Muslim Uighurs, Tibetan Buddhists, Christians and Falungong practitioners.
He described China's "war with faith" as "a war which they will not win".
The speech prompted a sternly worded response from the Chinese foreign ministry office in Hong Kong saying "we ask the US to respect the facts, stop the arrogance and prejudice and cease using religious issues to interfere in China's internal affairs".
Speaking to reporters in Taiwan on Monday during a forum on religious freedom, Brownback said his office has a list of hundreds of names of individuals in China who were missing and allegedly persecuted for their faith.
"Where are they? What is happening to them? Why can't their family members hear from them?" Brownback asked, challenging the Chinese government to respond to questions regarding the whereabouts of these individuals.
"The United States has designated (China) in its most problematic category of countries that persecute people of faith ... since 1999. And the situation has gotten notably worse in the last two years," he added.
"We are calling on alliances of countries and individuals to step up and to oppose these things when they take place."
According to UN experts, nearly one million Uighurs and other Turkic language-speaking minorities are being held in detention centres in Xinjiang. Beijing denied the claim saying they are in "vocational education centres".
Around half of China's 100 million Christians encounter persecution, "the worst it's been in more than a decade" following "new laws seeking to control religious expression," said Open Doors, a global advocacy group in a January report.
Brownback was in Taiwan for a two-day forum on religious freedom jointly sponsored by Taiwan and the United States.
President Tsai Ing-wen in her opening address said Taiwan will always choose to stand with "those who were oppressed and whose religious rights were taken away by authoritarian regimes".
"Taiwan knows how it feels when someone tries to take away your rights, wipe out your identity, and challenge your way of life," Tsai said in an apparent reference to Beijing's political and military pressure towards Taiwan.