epa06671026 A handout photo made available by the Saudi Press Agency (SPA) shows Saudi King Salman bin Abdulaziz waiting to receive other Arab leaders ahead of the 29th Arab Summit, in Dhahran, Saudi Arabia, 15 April 2018. The summit is held one day after the US, France, and Britain launched strikes against Syria on 14 April in response to Syria's suspected chemical weapons attack. Arab leaders are also expected to discuss tension with Iran, Palestinian issue, and developments in Yemen, Lebanon and Libya.  EPA/SAUDI PRESS AGENCY HANDOUT  HANDOUT EDITORIAL USE ONLY/NO SALES
Saudi King Salman bin Abdulaziz was not at his palace when the drone was shot down. EPA/SAUDI PRESS AGENCY HANDOUT

Saudis shoot down drone in Riyadh