CNN’s broadcast in Beijing of Thursday evening’s Democrat presidential primary debate was briefly blacked out as candidates discussed China’s human rights abuses against the Uyghurs.

CNN International correspondent Will Ripley tweeted a photo of a blacked-out television screen, reporting the channel’s feed went out when a question about the communist government’s mass detention of Muslim minorities in Xinjiang was asked. The United Nations estimates at least one million ethnic Uyghurs and other Muslims have been detained in Chinese concentration camps. It is unclear at exactly which moment in the debate that the feed was turned off.

CNN live feed of Democratic presidential debate goes to black in Beijing. Candidates were asked about China’s human rights record & the mass detention of Muslim minorities in Xinjiang. #PresidentialDebate pic.twitter.com/DSQ9QRu5zA — Will Ripley (@willripleyCNN) December 20, 2019

PBS host and debate moderator Judy Woodruff asked candidates whether the U.S. should do more than issue sanctions and pass resolutions targeting China in an effort to pressure them to halt their mass human rights abuses and asked if they would support a boycott of the 2022 Winter Olympics slated to be held in Beijing.

“I think any tool ought to be on the table, especially diplomatic, economic, and social tools like what you’re describing.” South Bend Mayor Pete Buttigieg replied. “For the president let it be known that his silence, whether it be on the rounding up of Muslim Uyghurs in Xinjiang, putting them into camps, or the aspiration of the people of Hong Kong for democracy, letting China know that his silence can be purchased is trashing American values.”

“The message I will send is if they perpetrate a repeat of anything like Tiananmen Square when it comes to Hong Kong, they will be isolated from the free world,” he added.

Despite the South Bend mayor’s assertions, President Trump has not remained silent on the Hong Kong protests, having signed two bills last month in support of their pro-democracy movement.

When asked by Woodruff what he would do as president if China invaded Hong Kong militarily, billionaire and climate change activist Tom Steyer said he would team with the U.S. allies to “push back” on Beijing’s aggression. “We have to work with them as a frenemy, someone who disturbs us and disagree with, but in effect, we are linked to in a world that is ever-getting closer,” said Steyer.

When the question turned to former Vice President Joe Biden, the Democrat frontrunner suggested beefing up the U.S. Navy’s presence in Asia. He then proposed bolstering ties with regional allies such as Japan and South Korea and said he would seek additional sanctions against Beijing at the United Nations.