A pro-democracy politician and four other people were injured when a knife-wielding man attacked protesters in Hong Kong Sunday.

The assailant slashed and stabbed people at Cityplaza mall, one of several shopping centers where protesters had gathered to demand government reforms for the 22nd straight weekend.

Local media reported the attacker told his victims that Hong Kong belongs to China.

Four men and one woman were taken to hospitals, where two were in critical condition.

Among the injured was politician Andrew Chiu Ka-yin, who had part of his ear bitten off as he tried to prevent the attacker from leaving the scene.

A pro-democracy activist tweeted that his "close colleague Dr Andrew Chiu was assaulted" and his "left ear was brutally halved."

The semi-autonomous city has been mired in more than five months of massive and often times violent protests, sparked by a proposed bill that would have allowed criminal suspects to be extradited to mainland China. The protests have evolved into demands for full democracy for Hong Kong, an independent inquiry into possible use of excessive force by police and complete amnesty for all activists arrested during the demonstrations. Masked activists have vandalized businesses and the city subway system, and attacked police with bricks and homemade gasoline bombs.

In September, Hong Kong leader Carrie Lam announced she would withdraw the extradition bill but that has not quelled the protests.

Hong Kong enjoys a high degree of autonomy under the "one government, two systems" arrangement established when China regained control of Hong Kong from Britain in 1997. But political activists and observers say Beijing is slowly tightening its grip on the territory and eroding its basic freedoms.