HONG KONG (Reuters) - Macau has suspended a pro-democracy lawmaker for alleged “disobedience” after he took to the street instead of staying on a sidewalk during a protest, as activists warn suppression of civil rights is growing in the China-ruled gambling hub.

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The suspension of the lawmaker is the first since 1999, when the former Portuguese colony returned to China within a “one country, two systems” framework that allows a free press and an independent judiciary, liberties denied on the mainland.

“It’s a dark day for Macau,” said Jose Coutinho, one of four legislators who voted against the suspension in Monday’s secret ballot, which drew 28 votes in favor. “I am sad and disillusioned with this outcome.”

There were numerous illegalities in the ballot and the lawmaker, 26-year-old Sulu Sou, should have been given an opportunity to defend himself, Coutinho added.

Sou is awaiting trial over a protest in 2016 against a perceived conflict of interest in the transfer of 100 million yuan ($15 million) from the charitable government-linked Macau Foundation to a Chinese university on whose board its chief executive, Fernando Chui, sits.

No date has been set for Sou’s trial, but the assembly vote strips him of his duties, and he can only return if he is found not guilty or gets a jail term shorter than 30 days.

Many in Macau fear the decision signals authorities intend to follow a path similar to that of former British colony Hong Kong, which has jailed several pro-democracy activists, including a lawmaker, Nathan Law, in the past year.

“This may be the beginning of the death sentence to Macau’s rule of law, and it will end up having an impact in the casino industry,” said Jorge Menezes, a lawyer who has lived in Macau since 1997.

“Sou was stripped of his rights to participate in the debate and vote in a clear violation of the assembly’s rules,” said Menezes, adding that such violations could apply elsewhere in Macau, including the casino industry.

Macau is the world’s biggest gambling hub, home to U.S. companies Las Vegas Sands, Wynn Resorts and MGM Resorts as well as Melco Resorts, Galaxy Entertainment and SJM Holdings.

The casinos have all reaped billions of dollars in the only place where Chinese citizens are allowed to gamble but will be at the mercy of authorities when their licenses start to expire in 2020.

Sou, who has challenged the government on several issues since becoming a lawmaker in September, vowed to fight on.

“We stick together for the very same goal that put us on this course to fight for justice,” grassroots supporter the New Macau Association, which has stood by him, said on social media site Facebook.