China's top diplomat in Hong Kong on Wednesday urged the general public to stand up against violence and denounce illegal behavior in a bid to quell the ongoing extradition bill protests in the territory.

Commissioner Xie Feng of China's Foreign Ministry said in an address at the Belt and Road Summit, a trade promotion event in Hong Kong, that the priority for Hong Kong in maintaining its competitiveness is to safeguard the rule of law.

"Some radicals in Hong Kong continued to escalate violent conflicts, arbitrarily trampling on the rule of law, endangering public safety, challenging national sovereignty and the bottom line of the 'one country, two systems' principle," Xie told the guests at the two-day international gathering of senior government officials and business leaders that began earlier in the day.

"Some foreign forces confuse right and wrong, shelter and pamper illegal violent acts and keep extending their 'black hands' to interfere. All those who love Hong Kong should bravely stand out and say no to violent behavior and tell the outlaws to stop, to maintain Hong Kong's gold-plated brand of rule of law and public order," he said.

Chief Executive Carrie Lam, speaking at the same event, expressed hope that the social unrest dies down.

"We are, to be sure, grappling with significant challenges, from the continuing trade dispute between the mainland and the United States to the recent social unrest here in Hong Kong," she said.

"Speaking of the latter, of Hong Kong, my fervent hope is that we can bridge our divide...find our way back to reasoned discussion, to the social stability essential to the long-term stability and prosperity and well-being of us all. I am confident we can do just that."

Protests involving people sometimes clashing with police and vandalizing subway stations have continued days after Lam last week announced the formal withdrawal of the now-suspended extradition bill next month.

High school students across the territory have for the past few days staged brief protests by forming human chains near their campuses before or after school, including those from some 16 schools who lined up streets in the Kowloon Peninsula on Wednesday, chanting the same slogans heard in protests in previous months in support of five demands.

Other than the withdrawal of the bill, protesters also demand an independent inquiry into alleged police brutality, amnesty for arrested protesters, retraction of the "riot" labeling of protests and democratic reform.