US President Barack Obama (L) is welcomed by Prince Khaled Bin Bandar Bin Abdul Aziz, Emir of Riyadh (3rdL), upon his arrival at King Khalid International Airport in Riyadh, Saudi Arabia, on March 28, 2014. Obama arrived in Riyadh for talks with Saudi King Abdullah as mistrust fuelled by differences over Iran and Syria overshadows a decades-long alliance between their countries. AFP PHOTO / SAUL LOEB