An attacker bit off part of a pro-democracy politician’s ear in Hong Kong on Sunday, during one of the most violent days of the demonstrations that have been rocking the city for months.

The knife-wielding man first slashed several protesters at the Cityplaza shopping center, then turned his rage on Andrew Chiu, a district councilor.

The crazed man grabbed Chiu’s head and bit off part of his ear before protesters tackled the suspect and badly beat him.

The attacker told the victims that Hong Kong belongs to China, according to local media.

Chiu was among five people injured as anti-government protesters again clashed with police in riot gear on the streets and inside crowded malls, leading to mass arrests.

Demonstrators ran amok in shops in two shopping centers and threw paint and debris at police, authorities said.

“Some masked rioters vandalized shops and committed arson,” city police said in a statement. “Some even placed nails on the roads, threatening the safety of all road users.”

Police said the protesters also vandalized a subway station linked to one mall and used umbrellas and cables to lock authorities out of another.

Hong Kong has been beset by violent protests since June, when pro-democracy residents took to the streets at first to condemn the city’s leaders over an extradition treaty that would transfer some criminal suspects to mainland China. The protests then expanded to include other rights issues.

One protester, 24, who gave her name only as Julie, gave police the middle finger Sunday as she said, “They come in here and push us around. It is not right.”

Protesters initially planned to gather at seven locations throughout the semi-autonomous city Sunday.

But cops were preemptively deployed at several of the locations, dispersing the gathering crowds. blocking access to some sites and arresting protesters.

Still, demonstrators were not deterred. Among the buildings trashed by protesters Sunday was the Hong Kong office of China’s Xinhua news agency.

“The practice of the … rioters once again shows that ‘stopping the violence and restoring order’ is Hong Kong’s most important and urgent task at present,” a representative for Xinhua said on Facebook.

With Post wires