Singapore has arrested 27 Bangladeshis suspected of having links with Islamic State and Al-Qaeda and deported all but one of them.

The alleged terror sympathisers were detained in November and December. The home ministry said members of the group routinely met a mosque and had considered carrying out armed attacks overseas. Investigations revealed they did not intend to attack Singapore but were planning jihadi style strikes in the Middle East and Bangladesh.

However, Home Minister K Shanmugam said in a Facebook post that the jihadi sympathisers "could easily have changed their minds and attacked Singapore."

The minister did not name the mosque the suspects used as a meeting point but local media reports said it was Angullia Mosque near Mustafa Centre, citing investigation documents.

"Our security agencies have done well in picking them up early. I had said yesterday that the threat of terrorism is real. We are getting daily reminders of that," Shanmugam added, according to Channel News Asia.

Fertile ground for terror

Following the Jakarta attack, the minister had said there was heightened concern that Southeast Asia was fast becoming a "fertile ground" for terrorism.

Investigations had revealed that the arrested men, who worked in the construction industry, were being primed by their handlers to eventually return to Bangladesh and join the growing terror network in the country. Bangladesh has recently seen a surge in jihadi-inspired attacks on free thinkers and bloggers.

Singapore Prime Minister Lee Hsien Loong said the arrested Bangladeshis were a serious threat to Singapore. "We are tightening up our security, and acting to protect our racial and religious harmony. Radicalisation and terrorism must never take root in Singapore," he said in a Facebook post.

Bangladesh said 14 of the 26 suspects deported from Singapore were jailed on terror charges. "We have freed 12 others after interrogation, but we are monitoring their activities," Maruf Hossain Sardar, a deputy commissioner of Bangladesh police, told Reuters.