Police reportedly fired tear gas on the first day of the Lunar New Year in Hong Kong on Saturday (January 25) after a crowd gathered to mark the fourth anniversary of the Mong Kok riots.

Video shows a protester hurling a water bottle at riot police.

"As protesters gathered to celebrate the anniversary of the 'fishball revolution' of 2016, riot police charged to disperse the crowd. Protesters ran away in front of the charge, some throwing water bottles on the police.

"The first day of the Lunar New Year was again marked by incidents as protesters and police kept carrying out a game of cat and mouse in the streets of Mong Kok," the filmer told Newsflare.