HONG KONG -- Hong Kong police condemned violent acts of rioters who blocked roads and assaulted police officers in Mong Kok on Saturday, the first day of the Lunar New Year.

As rioters threatened public security, the police had no choice but adopted the minimum force necessary to stop them, the police said in a statement in the small hours on Sunday.

Masked rioters gathered in Mong Kok and built up blockages with debris in areas surrounding Portland Street and the intersection of Nathan Road and Shantung Street on Saturday night, disrupting traffic. Some even attacked a police vehicle when officers were about to leave after law enforcement, said the statement.

The police always respect the right and freedom of residents to express opinions in a peaceful manner, the statement said, stressing that the police have to step in when illegal and violent incidents occur.