The violence reached a "life-threatening" threshold after a homemade bomb blast and knife thrust on officers, Hong Kong police said.

Demonstrations in Hong Kong broke out into violence last weekend after clashes between protesters and police on streets and shopping malls. A home-made explosive device remotely triggered a police car in the Kowloon district, authorities said it resembled the weapon used in "terrorist attacks."

"Violence has reached the threshold of life-threatening. It is not protestors, but rioters and criminals. There is no excuse for such actions," Hong Kong deputy police chief Tang Ping-keung said yesterday.

Black-dressed protesters also threw 20 petrol bombs at a riot police station, while many smashed shops and subway stations. An officer was stabbed in the neck with a knife but was not in danger of life.

Protests erupted in Hong Kong in early June to protest the extradition bill that allows Hong Kong to bring suspects to trial in jurisdictions without extradition treaties, including mainland China. . Hong Kong Special Administrative Region Chief Carrie Lam announced in early September a complete withdrawal of the bill, but protesters continued to take to the streets.