Yemen’s Houthis said they attacked “sensitive” sites in Saudi Arabia’s capital, Riyadh, with missiles and drones on Saturday, as flames and a large plume of smoke were seen near the city’s main airport.

Axar.az reports, citing Reuters, that Saudi authorities issued overnight alerts warning of possible aerial attacks in Riyadh and Al-Kharj before issuing an all-clear on Saturday morning. A Reuters journalist in Riyadh reported hearing explosions before the all-clear.

Saudi Arabia’s military coalition said its air defenses destroyed a missile launched toward Riyadh and foiled attacks targeting civilians in Bish, Farasan, Taif and Yanbu. It did not report whether the attacks caused damage.

The Houthis also claimed an attack on an Aramco facility in Yanbu, a major Saudi oil export hub, saying the operation was carried out in response to an attack in Sanaa.