SINGAPORE - Eight Bangladeshi men working in Singapore who were planning to stage terror attacks back home have been detained under the Internal Security Act (ISA), the Ministry of Home Affairs announced on Tuesday (May 3).

The men, aged between 26 and 34, called their group the Islamic State in Bangladesh (ISB) and intended to join terror group ISIS as foreign fighters in Syria and Iraq.

But as it was difficult to travel to the Middle East, they focused on returning to Bangladesh to topple their government through violent means, set up an Islamic State there, and bring it under the self-declared caliphate of the Islamic State in Iraq and Syria (ISIS).

They were detained last month (April 2016), in the first ISA detentions involving a terror cell of foreign workers.

Late last year, a closed religious study group of 27 radicalised Bangladeshi workers who had a significant amount of extremist material in their possession were arrested under the ISA, and deported. Their deportations were made public in January.

But in the latest case, the ministry said its investigations found that the men had identified possible targets for attack back home at the time of their arrest.

They also had documents on weapons and bombmaking, and raised funds to buy firearms to carry out the attacks in Bangladesh. An undisclosed amount of money has been seized.

The group's ringleader, Rahman Mizanur, 31, was an S-Pass holder in construction who set up ISB as a clandestine group in March this year.

He recruited the other seven, all Work Permit holders employed in the local construction and marine industries.

They are: Mamun Leakot Ali, 29; Sohag Ibrahim, 27; Miah Rubel, 26; Zzaman Daulat, 34; Islam Shariful, 27; Md Jabath Kysar Haje Norul Islam Sowdagar, 30; and Sohel Hawlader Ismail Hawlader, 29.

"ISB poses a security concern to Singapore because of its support for ISIS and its readiness to resort to the use of violence overseas," the Ministry of Home Affairs said in a statement on the detentions.

"The detained ISB members are still under investigation for their activities in Singapore. Rahman Mizanur has said he would carry out an attack anywhere if he was instructed by ISIS to do so, though there are no specific indications that Singapore had as yet been selected as a target," the ministry added.

Several of those detained may be liable for prosecution for terrorism financing, it said.

The detentions come at a time of mounting concern that ISIS is winning recruits from Bangladesh, which has recently seen radicals carrying out deadly attacks on minorities.

The ministry said a document titled We Need For Jihad Fight was recovered from Rahman Mizanur, which contained a list of Bangladeshi government and military officials who could be targeted. It included "media peoples" and "disbelievers".

He also possessed documents on weapons and bomb making, as well as a significant amount of ISIS and Al-Qaeda radical material which he used to recruit ISB members in Singapore from January 2016.

"The ISB members planned to recruit other Bangladeshi nationals working in Singapore to grow the group," the ministry added.

As part of the crackdown on ISB, another five Bangladeshi workers were investigated under the ISA. The ministry said investigations showed that they were not involved in ISB.

But they "possessed and/or proliferated jihadi-related materials, or supported the use of armed violence in pursuit of a religious cause".

All five have been repatriated to Bangladesh.

The ministry said the Singapore Government takes a very serious view of any form of support for terrorism.

"Any person, foreigner or otherwise, who engages in any activity that is inimical to Singapore's national security and racial and religious harmony will be firmly dealt with under the law. In this connection, foreigners should not import their own domestic political agenda into Singapore and carry out activities here in pursuit of such an agenda," it added.

The ministry said anyone who knows or suspects that a person has been radicalised, or is engaging in terrorist activities or propagating extremist teachings, should promptly inform the Internal Security Department on 1800-2626-473 or the police on 999.

Later on Tuesday, Minister for National Development Lawrence Wong and Parliamentary Secretary for Home Affairs Amrin Amin said the detentions are a reminder that Singapore has to take terrorist threat seriously.

Mr Wong wrote on Facebook that the issue was not about "foreign workers or Islam".

"It's about a minority of people who have chosen to distort religion, spread their own extremist ideology, and use terror and violence to achieve their goals," he said.

In a Facebook post, Mr Amin said, "The detainees and their likes pose a security concern to Singapore because of their support for ISIS and their readiness to resort to violence.

Though there are no specific indications that Singapore had been selected as a target, one of the detainees has said he would carry out an attack anywhere if he was so instructed by ISIS.

Thank you to our security agencies for their decisive handling! Stay alert, stay united and stay strong! ‪#‎SGSecure‬," he posted.