Photo/Illutration Firefighters and police inspect the main chamber of the Hong Kong Legislative Council after a pro-democracy lawmaker dropped a pot of pungent liquid on June 4. (AP Photo)

HONG KONG--A Hong Kong legislative debate was suspended Thursday afternoon ahead of an expected vote on a contentious national anthem bill after pro-democracy lawmakers staged a protest, with one dropping a pot of pungent liquid in the chamber.

Raising a sign that said “A murderous regime stinks for ten thousand years,” lawmaker Ray Chan walked to the front with the pot hidden inside a Chinese paper lantern. When security guards tried to stop him, he dropped the lantern and the pot, and was ejected from the meeting. Another lawmaker who accompanied him was also ejected.

Pro-democracy lawmakers see the bill, which would make it illegal to insult the Chinese national anthem, as an infringement on freedom of expression and the greater rights that residents of the semiautonomous city have compared to mainland China.

The pro-Beijing majority says the law is necessary for Hong Kong citizens to show appropriate respect for the anthem. Those found guilty of intentionally abusing the “March of the Volunteers” would face up to three years in prison and fines of up to 50,000 Hong Kong dollars ($6,450 or 703,950 yen).

Beijing began pushing for the law after Hong Kong soccer fans jeered the national anthem at international matches in 2015. As anti-government protests engulfed Hong Kong last year, thousands of fans booed loudly and turned their backs when the anthem was played at a World Cup qualifier match against Iran in September. FIFA later fined the Hong Kong Football Association over the incident.

Opponents of the bill see it as another sign of Beijing’s tightening control over the territory. China’s ceremonial national legislature formally approved a decision last week to create national security laws for Hong Kong that could see Chinese security agents posted in the city.

The legislative session coincided with June 4, the 31st anniversary of China’s bloody crackdown on pro-democracy protests in Beijing’s Tiananmen Square.

Before debate began, pro-democracy lawmakers stood in silence to mark the anniversary and put up signs on their desks that said, “Do not forget June 4, the hearts of the people will not die.”