Police scuffle with protesters who were demonstrating Sunday after Beijing issued an “interpretation” of the city’s constitution that effectively disqualified two newly elected legislators. (Isaac Lawrence/AFP/Getty Images)

China laid down the law to Hong Kong on Monday: Talk of independence, the Communist Party said, will not be tolerated.

China’s top legislature effectively disqualified two newly elected Hong Kong lawmakers for failing to take an oath of allegiance to the territory’s mini-constitution and instead advocating independence.

The move was seen as a major blow to the territory’s cherished autonomy and judicial independence.

Beijing’s decision, flagged in advance, sparked angry protests in Hong Kong on Sunday, with thousands of people taking to the streets in a demonstration reminiscent of the much larger ­pro-democracy Umbrella Movement in 2014. 

Police used batons and pepper spray to beat back protesters, and four people were arrested.

The latest troubles in Hong Kong flared after the two elected lawmakers, from a new pro-independence party, altered the oaths administered before taking their seats in the country’s Legislative Council — inserting a disparaging Japanese term for China, vowing to defend the “Hong Kong nation” and displaying a flag that read “Hong Kong is not part of China.” 

The oaths were ruled invalid, and attempts to redo them sparked chaos in the legislature. 

On Monday, Beijing put its foot down.

The Standing Committee of the National People’s Congress (NPC) issued its own “interpretation” of the Basic Law — Hong Kong’s mini-constitution, agreed to during the 1997 handover from British rule — an interpretation it said was binding on the territory. 

Any lawmakers who fail to take the oath of allegiance properly and violate the oath will be disqualified and will face legal consequences, it said. “Retaking the oath is out of the question once the initial oath-taking process has breached the legal requirements and been ruled invalid,” said Li Fei, chairman of the NPC’s Basic Law Committee.

The central government, he said, “is determined to firmly confront the pro-independence forces without any ambiguity.”

Advocating “separatism” is not a matter of political opinion but a major legal issue, Li said, and those doing so will need to be punished by law. “Traitors of the country will not have good endings,” he said.

The question of whether the two lawmakers — Sixtus Leung, 30, and Yau Wai-ching, 25, of the Youngspiration party — had the right to retake the oath was already being considered in a court in the southern Chinese territory. 

The Hong Kong Bar Association warned last week that any intervention by Beijing would deal a “severe blow” to the city’s judicial independence and undermine international confidence in its autonomy. Lawyers and barristers are already planning a “silent march” through Hong Kong on Tuesday.

While the NPC does have the right to interpret the Basic Law, it should not have done so while Hong Kong courts were actively considering the case, argued Johannes Chan, a law professor at the University of Hong Kong. 

“The implication is that ‘I don’t trust the courts, so I had better tell you what you should decide,’ ” he said. “So why should anyone trust the legal system?”

Hong Kong’s independent legal system stands at the heart of the “one country, two systems” model under which the territory was granted significant autonomy from Beijing.

Beijing’s move dealt that model a “fatal blow,” Chan said, and set the stage for further confrontation between the pro-democracy and pro-Beijing camps in the weeks ahead.

“I am very pessimistic, and I think it will get worse,” said Claudia Mo, a pro-democracy Hong Kong lawmaker.

“For Beijing, as soon as something starts, they want to shut it down,” she said. “This is the act of a coward.”

On Sunday, thousands of people marched through Hong Kong to voice their opposition to China’s decision to step in, holding signs saying “Defend the Rule of Law” and demanding that the territory’s Beijing-backed chief executive, Leung Chun-ying, step down. Police put the number at 8,000, but organizers estimated that 13,000 people attended.

In the evening, a smaller crowd gathered outside the Chinese government’s “liaison office” in Hong Kong and was faced by hundreds of helmeted police officers carrying shields.

Protesters tried several times to charge through police lines but were forced back, according to news agency reports. Police said they later took action to clear the streets and disperse the protesters. Two police officers were injured, one hit in the leg by a brick thrown from the crowd.

Some protesters wore masks and held umbrellas, in a deliberate echo of the 2014 Umbrella Movement, which staged a long sit-in to demand full democracy for the territory. 

But the extent of sympathy for the protests this time is unclear. Although many Hong Kongers fiercely guard the territory’s autonomy and would like to see greater democracy, only a small minority back the call for independence.

Beijing’s intervention is likely to anger many Hong Kongers and might swell the protesters’ ranks. Others, though, will probably condemn the protesters as troublemakers and dismiss their demands as unrealistic or undesirable.

In the South China Morning Post, political editor Gary Cheung wrote last week that the “antics” of the two lawmakers “only play into the hands of Beijing hardliners.”

Columnist Alex Lo also complained that their “childish display of defiance” would result in a further erosion of the authority of Hong Kong’s courts. “We all know that all-out antagonism of Beijing is just a lose-lose proposition,” he wrote.

Chan, the law professor, said Beijing’s response would lead to more polarization of opinion. 

“Very few people support what the two candidates have done, but this interference in the court process also generates a lot of resentment,” he said.

Luna Lin and Congcong Zhang contributed to this report.

Thousands in Hong Kong protest Beijing intervention

Beijing steps in as Hong Kong caught in standoff over China-cursing lawmakers