Saudi King Salman, Sheikh Mohammed bin Rashid and Sheikh Mohamed bin Zayed are pictured in Abu Dhabi this file photo from December 2016. The three leaders have long held close ties. AFP
Saudi King Salman, Sheikh Mohammed bin Rashid and Sheikh Mohamed bin Zayed are pictured in Abu Dhabi this file photo from December 2016. The three leaders have long held close ties. AFP

Saudi Arabia at 90: Sheikh Khalifa congratulates King Salman on National Day