Hi, everybody. This week, I'm speaking to you from our Nuclear Security Summit. I welcomed more than 50 leaders from around the world to make sure we're working together to meet one of the greatest threats to global security -- terrorists getting their hands on a weapon of mass destruction, like a nuclear weapon.
Fortunately, because of our efforts so far, no terrorist group has yet succeeded in obtaining a nuclear device or producing a dirty bomb using radioactive materials. But we know that al Qaeda has tried. ISIL has already used chemical weapons in Syria and Iraq. And if they ever got hold of a nuclear weapon or nuclear material, we have no doubt they'd use it.
That's why we've been leading a global effort to secure the world's nuclear materials. And with summits like this, we've made important progress. Working with other nations, we have removed or secured enough nuclear material for more than 150 nuclear
