Rioters set fire in Mong Kok on Sunday. Photo: Zhao Juecheng and Lu Wenao/GT

Eighty rioters were detained over the past weekend, Hong Kong police announced at a press conference on Monday, saying their violent actions would drag Hong Kong into "the state of no return."

Large numbers of rioters have gathered illegally in various districts in the city over the past weekend, obstructing traffic, damaging MTR and public facilities, violently attacking citizens, setting fire and smearing the Chinese national flag, police said at its Wan Chai headquarters. 

Tse Chun-chung, the Chief Superintendent of the Hong Kong Police Public Relations Branch, showed the pictures and video of violent incidents that occurred over the weekend. Self-made Molotov cocktails and a sharp weapon refitted from an umbrella were also presented at the press conference. 

He slammed the rioters and said their growing violent actions are dragging Hong Kong into "the state of no return."

Hong Kong police arrested 80 rioters on the weekend, including 69 men and 11 women, said Kong Wing-cheung, Senior Superintendent (Media Liaison and Communication) of the Police Public Relations Branch. 

The rioters were detained for illegal assembly, possessing offensive weapons, assaulting police and desecrating the Chinese national flag, Kong said. 

Kong also said four police officers were injured by rioters, with some hit by bricks.

1,556 rioters have been detained in the past three months as of Sunday, police said.