According to some estimates, Singapore, a cosmopolitan city‑state, has the most diverse population on earth. Within its 721.5 square kilometres, the resident population (5.8 million as of March 2020) ethnically comprises individuals of Chinese (76.2%), Indian (9%) and Malay (13.4%) descent. The main religions represented are Christianity (18.8%), Buddhism/Taoism (43.2%), Islam (14%) and Hinduism (5%). Four main languages are spoken, with English the working language.

The country has not seen terrorist attacks in the age of al‑Qaeda and Islamic State (IS). But one of Singapore’s closest neighbours, Indonesia, has repeatedly been targeted by the Jemaah Islamiyah (JI), al‑Qaeda’s principal offshoot in Southeast Asia, and other violent extremists. The most deadly incident in Indonesia was the Bali attacks of October 2002, which killed 202 individuals. Several other attacks in Indonesia through the decade were executed by the JI. Singapore itself has had close brushes with the group. The local JI cell’s plans to attack Mass Rapid Transit stations, government ministries and foreign embassies were interdicted by Singapore’s Internal Security Department (ISD) by the arrests of cell members in 2001 and 2002.

Since 2001, 94 individuals from the Muslim population in Singapore have been found to have been radicalised or involved in terrorism‑related activities at a level considered serious enough by the authorities to be placed under preventive detention, which is provided for under the Internal Security Act (ISA). Many have since been released, either after the lapse of a detention order (DO) or through the issuing of a ministerial direction suspending the detention (a suspension direction, or SD). Upon their release, ex‑detainees are typically for a time placed on restriction orders (RO), which restrict movements and impose other conditions, with the possibility of the individual again being detained if the conditions are not complied with or if there are signs of the individual being radicalised again. Others (mainly those judged to have been less involved in serious extremist activity or to pose less of a threat to society at large) were never detained but placed directly under ROs. Of those still in detention at the time of writing (July 2020), approximately six are individuals from the JI, while 16 are self‑radicalised individuals, mostly arrested in the 2010s, without formal affiliation to any extremist group (but with many showing sympathy for or declaring allegiance to IS).