A unit of Activision Blizzard Inc. has punished a player for expressing support for Hong Kong’s protest movement, the latest example of a U.S. company attempting to rein in speech that might displease the Chinese Communist Party.

Blizzard Entertainment said it was banning Ng Wai Chung, also known as Blitzchung, from its professional Hearthstone esports competition for a year. Blizzard is also withholding money he had already earned in the company’s top-tier Grandmasters tournament, which Ng said in a Twitter message cost him $10,000 of prize earnings. The move was triggered when Ng — dressed in a gas mask and goggles in defiance of authorities’ ban on face masks — used a slogan in support of Hong Kong’s pro-democracy protesters during a post-match interview.

“After an investigation, we are taking the necessary actions to prevent similar incidents from happening in the future,” Blizzard said in a statement. On Chinese microblogging site Weibo, the official account of Hearthstone reposted Blizzard’s statement in Chinese. “We will, as always, resolutely safeguard the country’s dignity,” it added.

Activision Blizzard joins a number of international companies finding themselves embroiled in controversy around free speech linked to China. Luxury brands like Versace, Coach and Givenchy have all fallen foul of Beijing’s demands to refer to both Hong Kong and Taiwan as parts of its territory and not suggest they are independent nations.

Even national darling and tech titan Huawei Technologies Co. found itself under fire for the way it represented Taipei in its phone software. And most recently, China’s state media halted NBA broadcasts after Daryl Morey, general manager of the Houston Rockets, tweeted an image supporting Hong Kong’s pro-democracy movement. During the summer, China also requested more than 40 foreign airlines stop referring to China, Hong Kong and Taiwan as separate countries.

“As you know, there are serious protests in my country now,” Ng said in a statement to gaming blog Inven Global. “My call on stream was just another form of participation of the protest that I wish to grab more attention.”

Activision Blizzard has tie-ups with Chinese gaming houses Tencent Holdings Ltd. and NetEase Inc. to distribute — and in some cases co-develop — new entries in beloved franchises like Call of Duty and Diablo in the world’s biggest video game market and beyond. There’s a lot at stake for the company, which happens to be part-owned by Tencent, as it ventures deeper into China.