Singapore's Ministry of Home Affairs has placed the son of Singapore Jemaah Islamiyah leader Mas Selamat Kastari under detention under the Internal Security Act, the ministry said on Thursday. Masyhadi Mas Selamat, 25, was detained on Nov. 21 last year under the Internal Security Act, which allows authorities to detain certain suspects under detention without trial. He will be under detention for two years. Masyhadi was arrested in Indonesia on Oct. 20 last year for his involvement in Jemaah Islamiyah, which has been classified as a terrorist organization. He was deported to Singapore on Oct. 30. The ministry said that Masyhadi went to religious schools in Indonesia since he was 13. He imbibed the organization's radical teachings and went through paramilitary training in Indonesia later. He formally became a member of the organization when he took an oath of allegiance at the age of 21. He had conducted surveillance activities and spread radical propaganda online for the organization, the ministry said. Mas Selamat Kastari is the leader of Jemaah Islamiah's Singapore cell. He is held in Singapore under the Internal Security Act (ISA) after his capture in Johor in April 2009 following his escape from a detention center in Singapore in February 2008. The Ministry of Home Affairs said on Thursday that two other Singaporeans were placed on Restriction Orders under the Internal Security Act for two years from December 2013. Zakaria Rosdan, 23, and Muhammad Khairul Sofri Osman, 29, were radicalized after searching for and viewing radical videos online. Zakaria had tried to contact a number of foreign militant organizations online. Khairul had encouraged Zakaria to do so. Those issued with a Restriction Order must abide by various rules. They will not be allowed to travel out of Singapore without approval from the Internal Security Department Director.