Graphic video showed a man lunging at the politician, who a colleague said was trying to stop a fight.
ADVERTISEMENTA Hong Kong lawmaker partially lost his ear after a man appeared to bite it off during an anti-government protest Sunday at a shopping mall, authorities confirmed.
A Hong Kong police spokesperson told NBC News the attack on Democratic Party member and district councilor Andrew Chiu occurred around 7:30 p.m. in the the Tai Koo district.
The suspect, who was not identified, was taken into custody, police said.
Another lawmaker, James To, told reporters the man slashed two people before attacking Chiu. In a statement, Hong Kong police said five people were taken from the mall to a hospital, where two were in critical condition.
In graphic video of the incident, several people can be seen trying to restrain a man when he breaks free and lunges at Chiu.
To told reporters afterward that someone found Chiu's ear, though it wasn't clear if it could be reconnected.
Chiu had been trying to stop a fight when the man attacked him, To added.
Protesters began gathering Saturday afternoon in districts across Hong Kong, authorities said. At one park,demonstrators billed the event as an "emergency call" for autonomy for the former British colony.
Hong Kong was to returned to China in 1997 under an agreement that allowed the region to maintain its freedoms for 50 years.
Sunday's demonstrations came nearly five months after protests first erupted over a bill that would have allowed suspects to be extradited to mainland China for trial.
The bill was later scrapped, though demonstrators have remained on the streets, rallying for democratic reforms and against police misconduct, among other demands.
The protests have sometimes turned violent. Police have responded with tear gas, pepper spray, water cannons and occasional live rounds. An officer was stabbed in the neck last month, and several protesters have been injured.