TOKYO (NYTIMES) - Last summer, Mr Halmat Rozi, a Uighur Muslim living in Japan, received a video call from his brother in China's western Xinjiang region. His brother said he had someone he wanted Mr Halmat to meet: a Chinese security officer.

Chinese President Xi Jinping had been invited to Japan, and the officer had some questions. Were Mr Halmat and his fellow Uighur activists planning protests? Who were the group's leaders? What work were they doing? If Mr Halmat cooperated, his family in China would be well cared for, the officer assured him on a second video call.

The officer's intent was clear - to discourage Mr Halmat from doing anything that might hurt China's reputation in Japan. The warning had the opposite effect. Mr Halmat had invited Japan's public broadcaster, NHK, to surreptitiously record the second call, which was later broadcast to millions of viewers.

The footage provided a rare look at Beijing's efforts to cultivate and intimidate Chinese ethnic minorities abroad and it has contributed to a growing awareness in Japan of China's repression of Uighurs in Xinjiang.

That, in turn, has increased pressure on the Japanese government to take strong action after years of tiptoeing around China, a dance that has left Tokyo out of step with its Western allies on the Xinjiang issue.

So far, Japan has mustered little more than expressions of "grave concern" over the fate of the Uighurs, hundreds of thousands of whom have been put in re-education camps in recent years in what critics say is an effort to erase their ethnic identity.

Japan is the only member of the Group of Seven industrial powers that did not participate in coordinated sanctions imposed on Chinese officials last month over the situation in Xinjiang, which the United States government has declared a genocide.

China's ruling Communist Party has rejected accusations of genocide in Xinjiang and is unlikely to cave to any amount of pressure over its policies, which it says are necessary to combat "terrorism and extremism".

But if Japan were to fully join the effort to compel China to end its human rights abuses there, it would add a crucial Asian voice to what has otherwise been a Western campaign.

As in the West, views towards China have hardened in recent years among the Japanese public - not just over Xinjiang but also over Beijing's crushing of democratic freedoms in Hong Kong and its military presence in the seas near Japan.

After years of ambivalence towards China, "public opinion has clearly shifted" and has "suddenly become extremely severe", said Professor Ichiro Korogi, a China expert at Kanda University of International Studies near Tokyo.

In some ways, the Japanese government's tone on China has already toughened. When two US Cabinet officials visited Tokyo last month, their Japanese counterparts signed a joint statement criticising China over its "coercion and destabilising behaviour" in the Asia-Pacific region and its violations of the international order.

But Japan's leaders and businesses have powerful reasons to hold their fire on China - a critical market for Japanese exports and investment. Any perceived criticism can quickly backfire, as Swedish fashion retailer H&M learnt last month when it became the target of a nationalist boycott in China for expressing concern about accusations of forced labour in Xinjiang's cotton industry.

By contrast, Japanese retail company Muji, which has more than 200 stores in mainland China, recently declared that it would continue to use cotton from Xinjiang despite the accusations.

Despite the economic and geopolitical risks, a growing group of lawmakers is calling for Japan to defend Uighur rights. Members of Parliament are working on legislation that would give the government powers to impose sanctions over human rights abuses. And a broad cross section of Japanese politicians were pushing Prime Minister Yoshihide Suga to cancel Mr Xi's state visit to Japan before it was delayed for a second time by the coronavirus pandemic.

The Uighur community in Japan, though estimated to be fewer than 3,000 people, has become more visible in the past year as it presses the government to act. Mr Halmat's story has played no small part. Since the broadcast last year of his call with the Chinese security officer, Mr Halmat - a fluent Japanese speaker - has appeared in the news media and before a parliamentary group to discuss the abuses in Xinjiang.

The stories of other Uighurs have also found a wider Japanese audience in recent months, including in a bestselling graphic novel featuring testimony from women who had been imprisoned in the Xinjiang camps.

As awareness has increased in Japan, concerns about Chinese human rights abuses have grown across the political spectrum.

For years, complaints about China's treatment of its ethnic minorities were considered the purview of Japan's hawkish right wing. Centrists and those on the left often saw them as pretexts for replacing Japan's post-war pacifism with the pursuit of regional hegemony.

But China's behaviour in Xinjiang has forced a reassessment among many liberals. Even Japan's Communist Party is calling it "a serious violation of human rights".

"China says this is an internal problem, but we have to deal with it as an international problem," Mr Akira Kasai, an MP and one of the party's top strategists, said in a recent interview.

Last summer, nearly 40 members of the Japanese legislature formed a committee for rethinking Tokyo's relationship with Beijing. In February, a long-standing conservative parliamentary committee dedicated to promoting Uighur rights expanded its membership to include lawmakers in the country's centre-left opposition parties.

The groups, said Ms Shiori Yamao, an opposition lawmaker, are pushing the legislature to follow in the footsteps of the US government as well as Parliaments in Canada and the Netherlands by declaring China's actions in Xinjiang a genocide.

Members of Parliament say they are also working on a Japanese version of the Global Magnitsky Act, the US law used to impose sanctions on government officials around the world involved in directing human rights abuses.

It is unclear how much traction the efforts will get. Mr Halmat does not believe that lawmakers will go so far as to accuse China of genocide, but he is hopeful that Japan will impose sanctions.

Speaking out

Mr Halmat came to Japan in 2005 for a graduate programme in engineering, eventually starting a construction company and opening a kebab shop in Chiba prefecture, on Tokyo's outskirts. He was not political, he said, and steered clear of any activities that might be viewed unfavourably by the Chinese government.

Everything changed in 2018 after he learnt that several members of his wife's family had been detained. Communication with his own family had also become nearly impossible amid the security clampdown.

The experience convinced Mr Halmat that he needed to speak out, and he soon began participating in protests calling for China to close the camps. Before long, he had become a prominent voice in Japan's Uighur community, making media appearances, meeting with politicians and running seminars on the situation in Xinjiang. When he received the surprise phone call from his brother, he knew that his activism had caught the attention of Chinese officials.

Since Mr Halmat's the appearance on the Japanese public broadcaster, the Chinese government has made no further attempts to contact him, he said. Phone calls to his family have gone unanswered.

He is afraid for his relatives. But speaking out has been worth it, he said. "Now pretty much everyone here knows about the Uighurs' problems."