Hong Kong football fans loudly booed China’s national anthem at a match in the Chinese-controlled city, defying Beijing days after Communist leaders tightened penalties for disrespecting the song.

Fans dressed in red in one section of the stadium jeered as the anthem, “March of the Volunteers,” was played at the start of a friendly game against Bahrain. Some waved banners reading “Fight for Hong Kong” and “Power for Hong Kong” while security personnel sought to prevent onlookers and some reporters from taking photographs of the banners and fans.

The long-simmering anthem controversy highlights increasingly tense relations between mainland China and the semi-autonomous former British colony, where pro-democracy activists say Beijing is tightening its grip.

It mirrors a similar debate in the United States, where some football players have kneeled on one knee when the “Star Spangled Banner” was played to protest racial inequality, prompting President Donald Trump to urge team owners to fire them.

Anthem jeering reflects the wider concerns of some Hong Kong residents determined to resist mainland China’s growing influence on the Cantonese-speaking territory.

They’re concerned Hong Kong’s high autonomy and unique cultural identity are being eroded, as Beijing asserts its authority and reneges on promises to let the city largely run its own affairs.

Tension over the booing in Hong Kong escalated this summer after the Chinese central government moved to toughen punishment for those caught disrespecting the song in public.

A new National Anthem Law came into effect in October, the same month nationalist-minded President Xi Jinping emerged from a Communist Party congress as the country’s most powerful leader in decades. Then, on Saturday, China’s legislature amended the criminal code so anyone disrespecting the anthem could be imprisoned for up to three years.

A local version of the law still needs to be drafted in Hong Kong and Macau, special Chinese administrative regions with separate legal systems and guaranteed Western-style civil liberties.

Some see the anthem law as specifically targeting Hong Kong football fans, who have frequently disrupted the anthem at the start of matches