Black smoke was seen rising near King Khalid International Airport in Riyadh on Saturday after overnight warnings of a “hostile aerial threat,” according to DW, citing reports from Reuters and AFP. Explosions were also reported in the area before Saudi authorities issued an all-clear.

Saudi Civil Defense told residents to stay indoors and avoid gathering or recording images. AFP journalists reported hearing two explosions, while Reuters said warnings had been issued in Riyadh and Al-Kharj, east of the capital, before the alerts were lifted.

Reuters published video and photographs showing a large plume near a highway leading to the airport, with the main terminal and other buildings visible in the foreground. Flight-tracking website FlightRadar24 reported “major problems” at King Khalid International Airport and placed it at its maximum disruption index.

No casualties or damage had been reported after the alerts ended. Saudi authorities had not said what caused the explosions or smoke. The country has previously reported intercepting missiles and drones launched by Yemen’s Iran-backed Houthi movement.

The incident came amid an escalation involving the Houthis and Yemen’s internationally recognized government, which is supported by Saudi Arabia. DW reported that the Houthis had denied a Saudi accusation that they targeted Mecca, calling it a “worn-out lie.”

DW also described wider tensions around Yemen’s Red Sea coast, including Houthi claims of Saudi strikes and the group’s announcement of a maritime blockade on Saudi Arabia. The supplied report did not establish whether the smoke near the airport resulted from an intercepted projectile, an impact or another cause.