They shouted slogans against police and also raised “five demands, not one less” chants of the anti-extradition bill campaigners.
Some of the protesters also broke into songs at times.
The flash mob also made long confetti with queuing tickets from restaurants run by the Maxim group. The business chain had become a target of protesters after the daughter of its owner criticised the agitators and backed the police at a UN human rights meeting in Geneva.
The mall in Kowloon Tong has been the scene of similar protests earlier also.