Singapore arrested 27 Bangladeshi construction workers under the city-state's Internal Security Act (ISA) for allegedly encouraging armed jihad against the Bangladeshi government, the Ministry of Home Affairs said.
Twenty-six of those arrested were members of a closed religious study group that supported armed jihad, the MHA said in a statement.
"Members were encouraged to return to Bangladesh and wage armed jihad against the Bangladeshi government. They had also sent monetary donations to entities believed to be linked to extremist groups in Bangladesh," the statement said.
"A number of the group members admitted that they subscribed to the belief that they should participate and wage armed jihad on behalf of their religion. Several of them contemplated travelling to and participating in armed jihad in the Middle East. Additionally, some of the group members supported the violent actions of extremist/terrorist groups that killed Shi'ites because they considered Shi'ites to be 'deviant.'"
Around 89 percent of Bangladesh's population of around 169 million is Muslim and most are Sunni.
The MHA said the group members took measures to avoid detection by authorities as well as sharing jihadi-related material among themselves and targeting recruitment of other Bangladeshi nationals to increase their membership.
"Investigations disclosed that while several members of the group had considered carrying out armed violence overseas, they were not planning any terrorist attacks in Singapore," the MHA said.
The remaining arrested Bangladeshi national was not a member of the group, but the MHA said he was believed to be in the process of being radicalized and also possessed jihad-related material.
Twenty-six of those arrested have been repatriated back to Bangladesh, while one is serving a jail sentence in Singapore for attempting to leave the country by "illegal and clandestine means" after learning that other members of his group had been arrested, the MHA said.
The High Commission of Bangladesh in Singapore said via email late Wednesday that authorities in Bangladesh are investigating.
"A Bangladeshi court has already sent 14 Bangladeshi suspects to jail in a case filed under the Anti-Terrorism Act," the statement said. "The concerned agencies of the Government of Bangladesh produced them before a court and the court placed them on a four-day remand. During the remand, they will be interrogated to find out about their alleged involvement."
It's unclear whether Bangladesh has much difficulty with terrorism tied to Islamic State. In October, the New York Times reported that U.S. officials warned Bangladeshi authorities terrorists tied to Islamic State were planning activity there. But Sheikh Hasina, the country's prime minister, called several attacks since then merely conspiracies by domestic opposition leaders to tarnish her government, even though Islamic State appeared to claim responsibility, the report said.
Last month, AsiaOne reported that the capital of Bangladesh, Dhaka, formed a 600-person police unit specializing in technology to combat militancy and terrorism amid an increase in the number of attacks on publishers, different Muslim sects and foreigners. The unit will focus on cybercrimes, terrorism financing and mobile-banking related crimes, the report said.
—By CNBC.Com's Leslie Shaffer; Follow her on Twitter @LeslieShaffer1