Three people were killed in two separate attacks that struck Saudi Arabia on Thursday. The first target was King Khalid International Airport in Riyadh, the country's capital. The second involved a Saudia Airlines aircraft, going by the account released by the kingdom. Anadolu Agency relayed the casualty figures to the wider public. No details have so far emerged about how the attacks were carried out or who was behind them. Because the airport ranks among the busiest gateways into the country, the breach raises sharp questions about security at one of its most visible links to the world.