A loud blast was heard at the airport in the Saudi capital Riyadh on Saturday, an eyewitness and people briefed on the matter said, amid an escalation of missile strikes on the kingdom by Yemen’s Iran-aligned Houthi group. The Saudi government’s media office and the Saudi civil aviation authority did not immediately respond to requests for comment. King Khalid International Airport urged passengers to contact their airlines directly and check their flight status before heading to the airport. Etihad Airways and Qatar Airways cancelled multiple flights between their respective hubs and Riyadh, with some cancellations extending into Monday.