SINGAPORE -- Alarm bells were raised at the Woodlands Checkpoint in Singapore on Friday morning when immigration officers found an illegal immigrant tucked away in the luggage compartment of a travel coach.

It was not escaped terrorist Mas Selamat Kastari, who broke out of a detention center on Wednesday, but a Sri Lankan man in his late 20s.

The officers arrested the illegal immigrant at 6.30 a.m. when they were conducting stepped-up checks on vehicles leaving the country.

The Malaysian bus driver, who in his late 20s and said to be in cahoots with the stowaway, was also arrested.

The 40-seater bus was not carrying any passengers nor any luggage.

Deputy Superintendent Tan Kong Hui, the deputy commander for counter terrorism and security, said: ?When we first found him, it is natural that we had linked him to the terrorist because that is who we are all looking for.?

Tan said preliminary investigations showed the illegal immigrant is not linked to Mas Selamat.

This was the first case of arrest made since the manhunt for the Jemaah Islamiyah militant started three days ago, said Tan.

Immigration checkpoints in Singapore have been put on high alert for the missing terrorist. The Straits Times-ANN