Foreign Militants in Iraq, Syria Have Doubled: Report

The figures, compiled by The Soufan Group, indicate that efforts by countries around the world to stem the flow of foreign militants to Iraq and Syria and blunt the appeal of violent organizations such as ISIL appear to have made little impact.

"The foreign fighter phenomenon in Iraq and Syria is truly global," the New York-based security consultancy's report said, Agence France Presse reported.

"ISIL has seen success beyond the dreams of other terrorist groups that now appear conventional and even old-fashioned," such as Al-Qaeda.

"It has energized tens of thousands of people to join it, and inspired many more to support it."

In all, between 27,000 and 31,000 foreign militants from 86 countries have traveled to Iraq and Syria, The Soufan Group said, compared to a figure of around 12,000 foreign militants in Syria when it last published a similar study in June 2014.

The largest number traveled to the two countries, across which ISIL controls a swathe of territory, from the Middle East and the Maghreb, with around 8,000 foreign militants each.

Around 5,000 made their way from Europe, with a further 4,700 from former Soviet republics.

The Soufan Group added that between 20 and 30 percent of foreign militants were returning to their home countries, creating major challenges for domestic security agencies as ISIL in particular looks to carry out an increasing number of attacks overseas.

ISIL claimed responsibility for a massive attack in Paris last month that left 130 dead, and its militants have been held responsible for violence in a litany of countries ranging from Iraq to Bangladesh.

The threat of returning foreign militants has sparked widespread debate, particularly in Western countries, many of which have criminalized travel to Syria to fight in the country's years-long conflict.

In the wake of the Paris attacks, American lawmakers have also called into question a program that allows Europeans to travel to the United States without a visa.

But, according to The Soufan Group, the latest figures are "evidence that efforts to contain the flow of foreign recruits to extremist groups in Syria and Iraq have had limited impact".

"As ISIL changes its focus from consolidating control of territory to attacking its foreign enemies in their own homelands, or their interests elsewhere, the profile of its foreign recruits will also change," it added.

ISIL seized control of significant parts of Syria and Iraq last year, committing widespread atrocities.

It has sought to recruit followers via social media, prompting growing alarm in the West, with the European Union launching a forum this month to bring together Internet giants like Google and Facebook as well as law enforcement agencies to combat online extremism.

The Soufan Group noted, however, that "while the power of ISIL' social media outreach is undeniable, it appears more often to prepare the ground for persuasion, rather than to force the decision".

"As hotbeds develop, recruitment through social media becomes less important than via direct human contact, as clusters of friends and neighbors persuade each other to travel separately or together to join ISIL.

"Even if ISIL is a failing enterprise in steady decline, it will be able to influence the actions of its adherents, and it may become more dangerous as it dies."