The arrests come after nine people, including six schoolchildren, from the group were arrested last week over an alleged plot to blow up Hong Kong courts, cross-harbour tunnels and the railways.
During last week’s operation, officers said they found chemicals that could be turned into TATP, an explosive, and bomb-making equipment in a Tsim Sha Tsui hostel.
Helmets, shields, air guns and walkie-talkies were also found, police said, adding that they had frozen bank funds of around HK$600,000.
The force said the group planned to launch car bomb attacks and place bombs in rubbish bins, alleging that they hoped to maximise the damage caused to society.