U.S. officials boosting security for July 4th weekend, just days after Turkey's airport terror attack. <script type='text/javascript' src='http://z.cdn.turner.com/cnn/van/resources/scripts/van-widgets.js'></script> <div data-cnnvansinglewidget data-affiliate='gantdaily' data-videoid='van/ns-acc/2016/07/01/PY-02FR_CNNA-ST1-1000000003670972' data-size='auto' data-autostart='true'></div>