Singapore has deported four Indonesians allegedly en route to Syria to join Islamic State, a media report said Tuesday.
The group, which included a 15-year-old boy, were arrested at a checkpoint as they made their way from Johor in Malaysia into Singapore, the Straits Times reported.
They were handed over to Indonesian authorities on the island of Batam, where they were questioned for five hours before being transported to Jakarta under heavy guard.
Singapore immigration officers detained the four because of their suspicious travel patterns, Helmy Santika, the police chief in Barelang City, told reporters in Batam.
Several days before being detained, they travelled from Batam to Singapore, then crossed into Johor, where they only spent three hours before returning to Singapore.
The Indonesian national police chief said that the four were linked to a radical ideologue who might have ordered the attacks on Jakarta on January 14 from his prison cell, the Straits Times reported. It was unclear whether the four were involved in that attack.