Saudi Arabia's civil aviation authority confirmed early Sunday that a missile strike on King Khalid International Airport in Riyadh killed 12 people and wounded 309, some critically. The dead include four Saudi citizens plus nationals from Bangladesh, the United States, Egypt, Jordan, Syria, Palestine and Sudan. The blast forced a full airport shutdown: flight-tracking data showed 271 Sunday departures - about 73 per cent - cancelled, with domestic terminals 3 and 4 taking the direct hit.

It was the third attack on the airport this week. Two earlier strikes killed four people and damaged a parked Saudi commercial aircraft. The Saudi-led coalition blamed Iran-backed Houthi rebels and called the strike a "fully-fledged war crime"; the Houthis claimed the two earlier airport attacks but have not claimed Saturday's.

President Trump told reporters Saturday the attack was "not acceptable" and said the United States "may" join Saudi strikes. Secretary of State Marco Rubio condemned what he called a "blatant disregard for innocent civilian life."

Saudi Arabia answered with its own retaliatory strikes Saturday across Houthi-held Yemen, with Houthi media reporting hits on Sanaa International Airport, the Bab al-Mandab Strait area and northern provinces.