Foreign fighters in the Syrian and Iraqi Civil Wars

Foreign fighters have fought on all four sides of the Syrian Civil War, as well both sides of the Iraqi Civil War. The conflicts are sectarian, with foreign Sunnis fighting for the Syrian opposition and the Islamic State, foreign Shias fighting for the Syrian government, and foreign leftists fighting for the People's Protection Units.

Many foreign nationals have fought in the conflicts and some of them have died. Fighters include those from the Gulf Arab states, Tunisia (following its own Tunisian revolution), Libya (following the Libyan Civil War), China, other Arab states, Russia's Chechnya and North Caucasus region, and Western countries. Estimates of the total number of foreign Sunnis who have fought for the Syrian rebels over the course of the conflict range from 5,000 to over 10,000, while foreign Shia fighters number around 10,000 or less in 2013. Over 600 foreign fighters were killed in the first half of 2013 alone. The Soufan Group reported on 15 October 2016 that there has been "a significant increase in the number of foreign fighters travelling to Syria" since 2014. The U.S. State Department reported on 2 June 2016 that their "intelligence community" estimates that possibly "in excess of 40,000 total foreign fighters have gone to the conflict [in Syria] and from over 100 countries" while six months prior, the Russian Defense Ministry estimated that there were about "25-30,000 foreign terrorist mercenaries are fighting for ISIL" alone.

The phenomenon causes concerns in the home countries of the foreign fighters. The phenomenon is not new, but the size and widespread origins in this case are unusual.

Jaysh al-Islam rebel leader Zahran Alloush called for foreign fighters to come to Syria.

According to figures collected by the Soufan Group, between 27,000 to 31,000 people including women and children who would not normally engage in conflict have traveled to Syria and Iraq to join the Islamic State and other extremist groups fighting in the region.

...
Wikipedia