Ali Soufan

The so-called Islamic State has suffered a series of setbacks in recent months, with key cities being retaken and the territory they are active in reducing in size greatly. Although scores of foreign fighters have been returning to their home countries, there remains a significant number of supporters still residing in the shrinking “caliphate”.

Of around 900 people from the Western Balkans who have gone to fight in Syria or Iraq, some 250 have returned to their home countries, according to a report published on Tuesday by the Soufan Centre, a US-based NGO dedicated to increasing awareness of global security issues.

Police forces on patrol pass under the closed Eiffel Tower in Paris, France, Saturday, Nov. 14, 2015. French President Francois Hollande vowed to attack the Islamic State group without mercy as the jihadist group claimed responsibility Saturday for orchestrating the deadliest attacks on France since World War II. (AP Photo/Kamil Zihnioglu)