Marine Corps Lt. Gen. Vincent Stewart, director of the Defense Intelligence Agency, testifies during a Senate Armed Services Committee hearing on Capitol Hill in Washington, DC, February 9, 2016. The global threat posed by the Islamic State group is still rising but US-based homegrown extremists pose the biggest danger to the homeland, Washington's top spy said February 9. In a report prepared for US lawmakers before he was due to address a Senate panel, Director of National Intelligence James Clapper said US-based extremists pose 'the most significant Sunni terrorist threat.' / AFP / Saul LOEB