The rare, coordinated effort has triggered a strong reaction from China, which retaliated with tit-for-tat sanctions against European politicians and scholars.

The European Union, the U.S., Canada and the U.K. imposed coordinated sanctions on top Chinese officials for human rights violations against the Uyghur minority, triggering Beijing to blacklist several EU politicians and academics.

The bloc accused the Chinese officials of being “responsible for serious human rights violations in China, in particular large-scale arbitrary detentions inflicted upon Uyghurs and people from other Muslim ethnic minorities.”

The bloc’s top diplomats imposed travel bans and asset freezes on four senior Chinese officials including Zhu Hailun, the former deputy party secretary in Xinjiang, and one of the architects of the mass-detention program, according to an investigation by the International Consortium of Investigative Journalists.

Zhu’s signature was on five of the six documents at the heart of the China Cables, which documented China’s use of prison-like structures and highly sophisticated mass-surveillance technology to detain and control members of the Uyghur community in Xinjiang.

The United Nations estimates that more than 1 million Uyghurs and members of other Turkic minorities were detained in camps. The number could be higher than 2 million, according to a U.S. State Department official.

China’s Foreign Ministry reacted to the EU sanctions by saying they “harm China’s sovereignty” and are “based on nothing but lies and disinformation, disregards and distorts facts.”

Beijing then announced a travel ban against eight European politicians and two scholars from Germany, Belgium, the Netherlands, Lithuania and Sweden. It also barred their institutions from doing business in China.

Dutch lawmaker Sjoerd Sjoerdsma, one of the politicians targeted, invited his European colleagues to continue to put pressure on China. “As long as China commits genocide on the Uyghurs, I will not remain silent,” he wrote on Twitter.

In solidarity with the bloc, the U.K. and Canada announced similar sanctions on the four Chinese officials and one company. The U.S. Treasury added two Xinjiang top officials to the blacklist of Chinese government representatives accused of being involved with “serious human rights abuses.” (The U.S. blacklisted Zhu and former Xinjiang Public Security Bureau Director Wang Mingshan, also on the EU list, last year.)

“We are united in calling for China to end its repressive practices against Uyghur Muslims and members of other ethnic and religious minority groups in Xinjiang, and to release those arbitrarily detained,” the three countries’ foreign ministries said in a joint statement.