Now that the Islamic State has fallen in Iraq and Syria, where are all its fighters going?

As the Islamic State clings to its last slivers of territory in Syria, the world is starting to grapple with a problem: Some of the 40,000 Islamic State supporters who migrated to the fight in Iraq and Syria are returning home. A study by the Soufan Center and the Global Strategy Network has tracked 5,600 fighters who have returned to their home countries.

These countries haven’t figured out how to address the returnees. Many are imprisoned, while others may be rehabilitated. These rehabilitation programs are difficult to design and run. Returning women and children born while their parents fought in Iraq and Syria present other challenges for re-integration.

While the returning fighters have not been directly responsible for any terror attacks or threats, they serve as an inspiration or model for those who might become radicalized or are becoming radicalized.

[U.S. and Britain are divided over what to do with captured ISIS fighters]

More than from any other country, 900 fighters are returning to Turkey. About 1,500 fighters from the country went to Syria and Iraq between 2014 and 2017. More than 3,000 fighters from Saudi Arabia went to fight, and 760 have returned home.

About 1,200 fighters have returned to Europe: 400 to the United Kingdom, 271 to France and about 300 to Germany. Of the 3,400 Russians who joined the fight in Syria and Iraq; 400 are returning.

Northern Africa is also a hot spot for returning fighters, with 800 coming home to Tunisia and nearly 200 to Morocco.

According to the report, seven fighters are returning to the United States. More than 250 Americans attempted to join the Islamic State in Iraq and Syria, with 129 travelling to join the fight. As of August 2017, the United States charged 135 people with terrorism-related offenses for their interactions with the Islamic State, and 77 have been convicted.

A new study by The George Washington University Program on Extremism has a slightly higher number of returning fighters to the United States. Researchers tracked 12 returnees to the United States, with nine being arrested and charged with terrorism-related offenses. The remaining three have not faced charges. The study notes that the main strategy for dealing with returnees has been through the criminal justice system, charging them with violations of the material support statute.

The rise and fall of the Islamic State in Iraq and Syria

After starting in Raqqa in late 2013, the Islamic State continued to acquire territory in Syria and Iraq until the end of 2015, when opposing forces started pushing the militants out of the cities. In late 2015, allied forces implemented better measures to restrict travel, and the flow of foreign fighters into Iraq and Syria slowed to a standstill. The Islamic State retreated from Mosul, its last urban center in Iraq, in July 2017. With the loss of Raqqa, the Islamic State’s remaining areas of concentration are mostly in Syria’s Deir al-Zour and Iraq’s Anbar Province, as well as a few scattered pockets elsewhere.