Two Indonesian men who planned to travel to Syria were denied entry into Singapore at the HarbourFront Ferry Terminal and sent back to Batam last Friday.

They were believed to be making plans to join the terror group Islamic State in Iraq and Syria (ISIS), and were also questioned by officers from Indonesia's special counter-terrorism unit Detachment 88 in Batam.

Yesterday, the two were flown back to their hometown of Pekanbaru in Riau province, where they remain in detention.

Pekanbaru deputy police chief Sugeng Putut Wicaksono told The Straits Times the two were bearing documents under the name of Muhammad Rizka Fajri, 27, and Firman Fitrialneldi, 30. Rizka Fajri was believed to be using false identity documents.

The website of Batam Pos newspaper cited Pekanbaru police chief Aries Syarief Hidayat saying police would engage religious leaders and psychologists to counsel them and try to correct their radical views.

More than 700 fighters from Indonesia are estimated to have joined ISIS, whose Malay-speaking unit Katibah Nusantara has put out recruitment videos online.

Indonesian officials have also stopped a number of men planning to travel to Syria through Turkey.