Greece has become a crossroads for extremists trying to reach Syria and Iraq from Europe and for fighters returning home. The fact that several members of the Paris and Brussels attack cell transited through the Greek island of Leros illustrates the Islamic State’s ability to exploit refugee flows in order to move fighters into Europe. Although Greece’s migrant crisis has eased recently, a persistent economic crisis has left the Greek government with limited resources and capability for border security and counterterrorism eforts. At a time of growing radicalization and Islamist extremist activity within Greece’s own borders, this has led to concern that the Islamic State may take advantage by launching attacks against Western or Russian tourists or interests on Greek soil.