HONG KONG -- Rioters took down the Chinese national flag from a pole and attacked police officers in an assembly held on Sunday afternoon at the Edinburgh Place in Hong Kong.

Footage showed several police officers arriving to retrieve the flag abandoned on the ground were besieged and assaulted by a large group of rioters at about 5:00 pm local time.

When police officers arrested people committing violent acts, rioters hurled miscellaneous objects at and assaulted them with intent to help the arrested people escape, the police said in a statement.

"In face of the serious threat to the safety of everyone at the scene and public order, police officers are deploying minimum necessary force to disperse the protesters," the statement said, adding that a person was arrested.

Given the chaos, the organizer had to announce the end of the event, but some rioters in black lingered and blocked roads with debris.