Officials have issued a stern warning to daredevils who’ve been...

Students take part in the protests in Hong Kong.

​The months-long protests in Hong Kong spread to the schools on Monday when thousands of students skipped the first day of class to call for democratic reforms after a weekend of violent unrest.

The university and secondary school students wearing helmets, goggles and masks gathered on a hilltop at Chinese University, making speeches and holding signs that said “Boycott for freedom” and shouting, “Reclaim Hong Kong.”

“I come here just to tell others that even after summer holidays end​,​ we are not back to our normal life, we should continue to fight for Hong Kong,” ​said a 19-year-old student who referred to himself as Chan.​

“If you are not a slave, don’t act like one,” said a woman ​identified as Chiu, ​as she urged her fellow students to fight for freedom.

Secretary of Education Kevin Yeung said schools weren’t the place for making “political demands.”

“We would like to keep schools as calm, peaceful and orderly places for students to study,” he​ ​told reporters.

​Beijing issued stern warnings to the protesters on Monday, with Chinese Foreign Ministry spokesman Geng Shuang saying the riots have “completely exceeded the scope of freedom of assembly. They have evolved into extreme and violent actions.”

​The state-run Xinhua news agency went further.

“The end is coming for those attempting to disrupt Hong Kong and antagonize China,” it said in an editorial.

The demonstrations erupted in March over a now-withdrawn extradition bill that would have allowed suspects from semi-autonomous Hong Kong to be transferred to mainland China for prosecution.

Since then, demonstrators have sought democratic reforms for the former British colony that was returned to China in 1997.

The unrest escalated over the weekend as protesters burned barricades and threw gasoline bombs at police, who retaliated with tear gas, water cannons and batons.

Demonstrators blocked roads and disrupted public transportation leading to Hong Kong’s international airport, while others targeted the subway system, tearing out turnstiles and smashing CCTV cameras.

Carrie Lam, Hong Kong’s chief executive, said 10 subway stations had been damaged by “violent offenders.”

Beijing on Monday reiterated its support for Lam.

​”​China’s central government supports chief executive Carrie Lam’s leadership … to administer in accordance with the law and supports Hong Kong’s police tackling the violence and chaos in accordance with the law to restore order,” ​Geng said.

With Post wires