LOS ANGELES, CA - JULY 02: A U.S. Customs and Border Protection officers watch over travelers at Los Angeles International Airport on July 2, 2016 in Los Angeles, California. Security is stepped up for the busy Fourth of July travel weekend following deadly attacks on an airport in Turkey that claimed 44 lives, and in Bangladesh where 20 hostages were killed. A pro-ISIS twitter account threatened attacks at airports in Los Angeles, London Heathrow and New York JFK airports but officials are doubting its credibility. (Photo by David McNew/Getty Images)
