Chinese President Xi Jinping arrives for this week's Nuclear Security Summit in Washington, D.C. Rough Cut (no reporter narration).
NATURAL ROUGH CUT (NO REPORTER NARRATION) Chinese President Xi Jinping arrived in the U.S. on Wednesday (March 30) for this week's Nuclear Security Summit in Washington, D.C. Just as fears of nuclear terrorism are on the rise, President Barack Obama's U.S.-led drive to lock down all vulnerable atomic materials worldwide risks losing momentum. Obama will convene the global summit, bringing together more than 50 countries, in the aftermath of deadly militant attacks in Brussels that have fueled concern that Islamic State could eventually target nuclear plants and develop radioactive "dirty bombs." But despite significant progress in persuading countries to protect or rid themselves of bomb-making materials, much of the world's plutonium and enriched uranium remains poorly secured. At the same time, the effort has been complicated by fresh nuclear advances by North Korea and diplomatic tensions between the United States and Russia. All of this weighs on Obama's agenda as he prepares to host world leaders for his fourth and final Nuclear Security Summit on Thursday (March 31) and Friday (April 1). He inaugurated the event nearly six years ago, early in his tenure, after using his landmark 2009 Prague speech to lay out the goal of eventually ridding the world of nuclear weapons as a central theme of his presidency.