SINGAPORE - There is a need for a concerted international strategy to deal with the underlying causes of radicalisation, Home Affairs and Law Minister K Shanmugam said on Wednesday (Thursday morning Singapore time), as he urged the United States to get involved in efforts to counter the root issues that may drive people to extremism.

Mr Shanmugam was speaking on the conflict in Syria and radicalisation in Southeast Asia on a visit to Washington DC, amid international concern over the trend of foreign fighters for terror group ISIS returning from Syria and Iraq who are seeking to set up caliphates in their home regions.

"What we intend to do in SoutheastAsia, we are trying to get together a group of like-minded countries to come together, such as Australia, New Zealand, Singapore, Malaysia, and Indonesia, to try and deal with these issues," Mr Shanmugam said.

"We may not be able to deal with all of them but at least we have a platform to start trying and talk about these issues and possible solutions. But America has to get involved, other countries have to get involved."

The cost of getting started at this stage is relatively low, but will be much higher later on, he added. And while many countries have focused on downstream consequences, taking out terrorist leaders, dismantling organisations, and taking aim at the finances of terrorist groups, this is not enough.

"If we do not deal with the underlying philosophy and the underlying causes, in the end, as long as you do not deal with that, as long as you do not deal with people's views which need them to be radicalised in the first place, all you will be doing is cutting out their heads and new heads will come up," said Mr Shanmugam.

He was speaking at a seminar organised by the Johns Hopkins School of Advanced International Studies and Singapore's S. Rajaratnam School of International Studies. Mr Shanmugam is on a visit to the United States from April 25 to 28.

During his speech, he laid out the threat posed by returning foreign terrorist fighters, as well as Singapore's strategies in countering extremism and terrorism.

Southeast Asia, he pointed out, has been a target for the Islamic State of Iraq and Syria (ISIS) with its sizeable Muslim population.

The militant group has made known the places they want to establish a caliphate: Indonesia, Malaysia, and parts of Southern Philippines. There are also about a thousand fighters from the region who have travelled to Syria and Iraq to fight, forming their own combat unit.

"ISIS has become much more effective in reaching out to this region," the minister said.

And while the threat Southeast Asia faces may seem far removed from the US, he added that "what you are seeing is a replay of what is happening in other parts of the world".

"At first it's not urgent, it's not immediate, there's no kinetic activity," he said, citing the situation of fighters returning from Afghanistan.

He added: "Today in Syria and Iraq, history is repeating itself. People are going there, they are learning, they are trained in the latest techniques, and then they are going to come back to various parts of the world, including Southeast Asia."

And the rise of political Islam - for reasons such as the availability of online material, and money from the Middle East being used to fund kindergartens and schools - in Southeast Asia makes the region fertile ground for radicalisation.

The implications from such developments will shake not just countries in the region, but American assets here, and the US itself, he noted.

Mr Shanmugam also highlighted how 200 terror detainees will be released from prisons in Indonesia over this year and the next. The country, he noted, has no laws to detain people who pose a serious threat. And even if they have not been fully radicalised in prison, they will present a risk, he added.

This will happen in significant ways in the next 18 months, said Mr Shanmugam. It has already begun, with attacks being planned from within Indonesian prisons.

Even as efforts to tackle the root causes behind radicalisation get off the ground, Mr Shanmugam cautioned against the risk of Islamophobia gaining ground.

"That, you have got to try and avoid. If you get into Islamophobia, it will make your populations feel anti-Muslim, anti-Islam. That just feeds the terrorists. It's a big risk," said Mr Shanmugam. "We need to guard against that, and fight it. The vast majority of Muslim populations in most places are moderate and peaceful."

Accompanying him on his visit to the US are officials from the Home Affairs and Foreign Affairs Ministries, said the Home Affairs Ministry in a press statement.

On April 26, he met US Secretary of Homeland Security John F Kelly in Washington DC - their first meeting since Mr Kelly's appointment - and exchanged views on the threat of global terrorism and the challenges posed by radicalisation in Southeast Asia.

On April 27 he is slated to meet Mr Thomas Bossert, Assistant to the President on Homeland Security and Counter-terrorism. He will also have separate bilateral meetings with senior officials from the Federal Bureau of Investigation , Central Intelligence Agency, and Office of the Director of National Intelligence. At these meetings, he will reaffirm the good security cooperation between Singapore and the US, the ministry said.