The "Islamic State" (ISIS) terrorist group lost around 14 percent of its territory in 2015, while Syria's Kurds almost tripled the land they control, thinktank IHS Jane's said on Monday, according to AFP.
The development is a blow to the group given that its aim is to capture and hold territory to expand its so-called "caliphate", where it imposes a severe and bloody form of what it calls Islamic law.
The jihadist group's losses include the strategically important town of Tal Abyad on Syria's border with Turkey, the Iraqi city of Tikrit, and Iraq's Baiji refinery.