The Boston bombings have brought attention to the tumultuous Russian region of the North Caucasus, including Dagestan and Chechnya, which was a front line for international jihadists in the mid-1990s and which has seen a series of fierce and ultimately futile battles for independence from Russia.
In recent weeks, North Caucasus-based fighters became increasingly visible online, as well as on the ground in Syria. Along with a growing number of foreign fighters from the Arab world as well as Europe, they joined a legion of al-Qaeda offshoots and Syria-based movements to fight against the regime of Bashar al-Assad.