SINGAPORE -- Immigration checkpoints in Singapore have been placed on high alert to ensure that a fugitive terror suspect does not flee the country.

Mas Selamat Kastari, 47, who authorities said headed the Jemaah Islamiyah (JI) terror network here, escaped from the Internal Security Department's Whitley Road detention center on Wednesday afternoon.

Singapore authorities have tightened checks at various land, sea and air checkpoints.

At the Woodlands Checkpoint on Thursday, armed Gurkha guards were seen patrolling the area.

A helicopter was also spotted circling the skies over the area.

At the Tanah Merah Ferry Terminal, where ferries leave for the Indonesian islands of Bintan and Batam, immigration officers have put on bullet-proof vests.

Mas Selamat was caught in Bintan in 2003 for carrying false identification papers.

Home Affairs Minister Wong Kan Seng told Parliament on Thursday that security at all checkpoints has been tightened.

Police were also stepping up checks beyond “not the normal immigration clearance areas,” said Wong.

Much of Singapore's shoreline is lined by thick forests and certain areas such as Lim Chu Kang, Admiralty, Tuas and Changi are known to be places where illegal immigrants have sneaked in from the seas.

They either swim or come in motorized sampans.

The stepped-up checks caused minor delays for travellers. Massive traffic jams at both checkpoints in Tuas and Woodlands occurred during the evening peak-hour as officers inspected every car leaving the border for Malaysia.

They asked drivers and passengers to step out and examined the car, including the boot, thoroughly.

Those who left Singapore at these checkpoints also noted that immigration officers gave more than just the normal cursory look at their passports.

Indonesia and Malaysia have also been asked to keep a look out for Mas Selamat. The Straits Times