In 1963, shortly after the events of the Indonesia-Malaysia confrontation, the government took action against several opposition politicians and activists. SF was seen as pro-Indonesia and pro-China, causing the Socialist Front leader's arrest. Among those detained and arrested were Ahmad Boestamam (PR president), Ishak Haji Muhammad (PBM president), Abdul Aziz Ishak (Gerakan Angkatan Melayu Sedar president) and Datuk Kampo Radjo (later to become president of the PRM), Tan Kai Hee, Tan Hock Hin, Dr. Rajakumar, Hasnul Hadi, Tajuddin Kahar and hundreds of others. Rallies and mass demonstrations were held on 13 February 1965 in Kuala Lumpur in conjunction with the second anniversary of the detention of Ahmad Boestamam and others to oppose the mass arrests of activists and leaders of the SF under the Internal Security Act (ISA) and the alleged involvement in "subversive" activities.