HONG KONG -- Hong Kong police expressed "severe condemnation against masked rioters," who committed organized destructive acts, blocked traffic and assaulted police officers in various districts on Sunday.

Since 1:00 pm local time Sunday, various groups of protestors gathered at malls in different districts including Sha Tin, Tuen Mun, Tai Po and Taikoo. Some masked rioters later vandalized Mass Transit Railway facilities and shops in the malls extensively in an organized manner, and blocked exits of the shopping malls, said a police statement released early Monday.

Masked rioters popped up in various shopping malls to escape from police. Police said, in response to the crimes, their officers entered the malls to embark on the arrest operations.

When police handled the cases in the malls, some rioters threw miscellaneous objects from height at police officers. Some rioters surrounded, scolded and assaulted people with different political views.

Police said that "masked rioters' blatant defiance of the law cannot be condoned. Police strongly condemn these acts."

At around 7:30 pm local time, a wounding case happened in Taikoo Shing, in which five people were sent to hospital and two of them are in critical condition.

"Police strongly condemn violent acts and will conduct active and thorough investigation with a view to bringing offenders to justice, regardless of their motive and background," the statement said.

At night, some masked protestors damaged traffic lights, and built barricades with miscellaneous objects including minibus stands, rubbish bins and railings, blocking carriageways.

Police reiterated that "no violent behavior will be tolerated," saying they will continue to take resolute enforcement action so as to safeguard Hong Kong's public safety and bring all lawbreakers to justice.