U.S. President Barack Obama, right, listens as King Salman bin Abdulaziz Al Saud of Saudi Arabia speaks during a meeting in the Oval Office at the White House in Washington, D.C., U.S., on Friday, Sept. 4, 2015. "This is obviously a challenging time in world affairs, particularly in the Middle East," Obama told reporters, mentioning energy near the end of a list of topics that he and Salman would address. Photographer: Olivier Douliery/Bloomberg via Getty Images
