Three Saudi citizens were killed and several others wounded in two attacks Thursday targeting King Khalid International Airport in Riyadh and a Saudia Airlines aircraft, Saudi Arabia’s General Authority of Civil Aviation said Friday.

The attacks mark the deadliest assault in the kingdom since Saudi Arabia and allied forces launched a major military offensive last weekend against the Iran-backed Houthi rebels in neighboring Yemen.

The first attack on Thursday targeted airport facilities, while the second struck the aircraft, according to a statement from the General Authority of Civil Aviation. The statement did not identify those responsible, though the Houthis claimed to have targeted the airport with a ballistic missile.

The airport has been the target of multiple attacks, with a Sudanese national killed there earlier this week.

The General Authority of Civil Aviation noted that the injuries sustained by citizens and residents of different nationalities ranged from minor to serious. The authority also indicated that operational activities at the airport had returned to normal.