LAWS AND SYRIAN CONFLICT
Several countries are examining laws that would prevent its citizens from leaving to join the Syrian conflict.
And Britain, which has the largest number of foreign recruits in ISIS' ranks, wants laws to prevent them from returning.
It also wants the power to revoke the citizenship of those who hold dual citizenship.
All this is in response to the Sunni extremist group's power in recruiting foreign fighters.
There are about 12,000 foreign fighters involved in the three-year-old Syrian conflict, which has now spilled over into Iraq.
Dr Rohan Gunaratna of Singapore's International Centre for Political Violence and Terrorism Research said ISIS "has attracted many radical Muslims who believe they are joining because they are answering a call by God, but this view is not shared by a majority of Muslims here."
ISIS had declared the establishment of a caliphate known as the Islamic State, with its leader Abu Bakr as the caliph.
It also declared that Muslims all around the world must pledge their allegiance to the new caliph. But the Internet has been a game changer too, with ISIS spreading its agenda online, especially via social media.
In an oral reply to Parliament on July 9, Deputy Prime Minister Teo Chee Hean said: "Youths, who are the primary users of social media, are particularly vulnerable to such propaganda.
"It is not possible to completely insulate Singaporeans from the radical rhetoric that is so prevalent online.
"Singaporeans therefore must play their part to prevent loved ones and friends from becoming radicalised and embarking on a path of violence and self-destruction."
Dr Gunaratna said foreigners who join ISIS now are unlike those who joined the fight in Afghanistan in the 1980s and 1990s.
Many of those combatants would bring back what they learnt to their home countries.
But those who join ISIS are joining "group terrorism and they will have an ideology that will compel them to carry out attacks anywhere in the world", added Dr Gunaratna.
A number of Singaporeans are in Syria, including a woman who joined her foreign husband and two teenage children.
DPM Teo told Parliament: "The whole family is taking part in the conflict in various ways, either joining the terrorist groups to fight, or providing aid and support to the fighters."
Several others who had intended to travel to Syria or other conflict zones to engage in the jihadist violence were intercepted.
DPM Teo had said: "We have established that they were radicalised by videos, articles and social media postings online.
"They subscribed to the sectarian-religious or ideological rhetoric that calls for engaging in militant jihad in Syria."