U.S. President Barack Obama (L) shakes hands with Saudi Arabia's King Salman at the start of a bilateral meeting at Erga Palace in Riyadh January 27, 2015. Obama sought to cement ties with Saudi Arabia as he came to pay his respects on Tuesday after the death of King Abdullah, a trip that underscores the importance of a U.S.-Saudi alliance that extends beyond oil interests to regional security. REUTERS/Jim Bourg (SAUDI ARABIA - Tags: POLITICS TPX IMAGES OF THE DAY)