Five people have been injured in a knife attack at the site of a pro-democracy protest in Hong Kong.
The attack happened at the Cityplaza mall in the Tai Koo district on Hong Kong Island.
The local hospital authority said four men and one woman were injured, with two in critical condition.
One of the injured, a local councillor, had his ear partially bitten off by the as-yet unidentified male attacker, who was subdued by passersby in the mall.
Witnesses said the Mandarin-speaking attacker drew a knife after a political argument with people in the mall, which was the site of pro-democracy protests earlier in the day.
The local councillor, Andrew Chiu Ka-yin, reportedly was attempting to prevent the attacker leaving the scene when the man bit off a section of his ear. Witnesses said the attacker was badly beaten by passersby who intervened, before police arrested the man.
One of the victims, a woman, told the South China Morning Post that the suspect drew a knife after arguing with her sister and her husband, who were also injured. The Hong Kong Free Press reported that that attacker was a Mandarin-speaking pro-Beijing supporter.
Hong Kong has experienced five months of sometimes violent demonstrations by pro-democracy activists, who first took to the streets to protest against a bill that would have allowed extradition to mainland China, but evolved into a broader revolt against the way Hong Kong is administered by Beijing.
The wave of pro-democracy protests continued this weekend, days after a high-profile activist, Joshua Wong, was banned from standing in local elections. Police fired tear gas on Sunday into crowds of demonstrators in the eastern suburb of Taikoo Shing, home to the Cityplaza where the stabbing occurred.
With no end in sight, China's leaders signalled last week that they were preparing to change how the mainland administered Hong Kong.
Shen Chunyao, the director of the Hong Kong, Macau and Basic Law Commission, told reporters that officials were looking at ways to "perfect" how Hong Kong's chief executive was appointed and removed. He did not elaborate on what exactly might change.
Last month, the leader of one of Hong Kong's largest pro-democracy groups was taken to hospital after being attacked, apparently with hammers. Photographs on social media showed Jimmy Sham of the Civil Human Rights Front lying in the street, covered in blood.
From hospital, the activist said he "remained committed to the ideal of peaceful non-violence".
Violence of crisis continues to intensify
Stephen McDonell, BBC News, Hong Kong
Images and footage of the incident spread quickly around social media platforms. The man who did the biting was subdued by a crowd, which then beat him, some using metal objects.
That is was all happening in a shopping centre being stormed by riot police in pursuit of protestors who were earlier singing and chanting made it even more intense. A small group of hardcore activists had also smashed up shops whose owners they judged to be too "pro-Beijing".
I watched the footage on a television in a small restaurant in Hong Kong. Halfway through the report, the woman running the place turned and walked away from the screen. "This is all too depressing," she said in Chinese.