Defense Secretary James Mattis said the U.S. is going to focus on killing remaining foreign fighters in the Islamic State. "Because the foreign fighters are the strategic threat should they return home to Tunis, to Kuala Lumpur, to Paris, to Detroit, wherever. Those foreign fighters are a threat," he said. "So by taking the time to deconflict, to surround and then attack, we carry out the annihilation campaign so we don't simply transplant this problem from one location to another."
"I'll leave that to the generals who know how to do those kind of things. We don't direct that from here," he added. "They know our intent is the foreign fighters do not get out, I leave it to their skill, their cunning, to carry that out."
via pjmedia.com
I can see how this would be the militarily preferred option, but is it quite legal? What if ISIS fighters are trying to surrender?