Places of worship should not be turned into fortresses but remain welcoming and open, Law and Home Affairs Minister K. Shanmugam said yesterday, as he called on the wider community to instead counter radical ideologies by educating young people against far-right extremism.

Speaking to the media after a meeting between Christian and Muslim leaders at Yusof Ishak Mosque in Woodlands, the minister responded to a suggestion that religious groups here beef up security at locations where worshippers gather.

"You go to a place of worship, you are approaching with a spiritual mindset. You are going there because you want spirituality, or you have problems or in some way you want a conversation with a higher being," said Mr Shanmugam.

"If we started turning places of worship into fortresses, how welcoming is that going to be? And is it really going to be effective anyway? I think we have to have a sense of balance here."

While those in charge of places of worship should be more alert, he said he would be careful about religious groups enhancing security measures.

"Security is everyone's business. Every person has got to look at things - are there bags left somewhere? Is someone behaving in a way that is odd? These are cues that one has got to pick up.

"We try to do that education through SGSecure," said Mr Shanmugam, referring to the national movement to sensitise, train and mobilise Singaporeans to play a part to prevent and deal with a terrorist attack.

Saying Singapore's emergency forces are also ready to respond to threats, he added: "But I think we also need to keep our way of life, and our way of life means religious institutions are welcoming and open."

The minister had attended a meeting yesterday morning between Christian and Muslim religious leaders, following the disclosure of a plot by a Protestant Christian youth to attack Muslims at two mosques here - Yusof Ishak Mosque and Assyafaah Mosque in Sembawang.

The 16-year-old Singaporean of Indian ethnicity has been detained under the Internal Security Act (ISA).

At the meeting, the religious leaders reaffirmed the mutual trust and understanding between the two religious communities, and condemned the terror plot.

Mr Shanmugam said he was heartened by the strong statements put out by the various religious authorities following news of the youth's detention, adding that Singapore's religious harmony, which is seen as a way of life, is unique and must be protected.

He noted that Minister for Culture, Community and Youth Edwin Tong, a Catholic, was the guest of honour at the Thaipusam festival yesterday at Sri Thendayuthapani Temple in Tank Road.

Asked if the youth's case will be heard in open court, Mr Shanmugam said the 16-year-old will get a hearing within the rubric of the ISA, with access to a lawyer. He added that the youth's parents are also fully involved in the process.

"If you went through the criminal process and the question is 'what has he actually done', then it will be argued that he hasn't done anything. In many countries, that is part of the issue. You've got to wait for them to do something, and often, that's too late.

"I think our people support the approach where we intervene very early," said Mr Shanmugam, who added that the case is not suitable for open trial.

He said letting the youth take the stand in a trial would also give him a platform to talk about his manifesto and what he has against Muslims, which is detrimental for inter-racial confidence here.

"You will get reactions from the Muslim community. You will get other people from the Christian community who listen to this, and maybe some may think of this boy as being victimised.

"You run the risk of a Christian-Muslim divide, or deepening a divide," said Mr Shanmugam.

He added that Singapore takes a different route from many other countries in using the ISA. But its record of racial and religious harmony over the last 50 years is proof that it works. "So, it's not the theory, it's the practice," he said.

Mr Shanmugam said that in the last two decades, the Internal Security Department (ISD) has prevented attacks in Singapore, stopping radicalised individuals from going overseas to conflict zones to fight, and disrupting plots by foreigners, both here and abroad.

He added that since 2015, ISD has picked up 53 individuals under the ISA for terrorism-related conduct, of which 37 were detained and 16 issued with Restriction Orders.