At least 12 people have been killed and 309 injured in an attack on King Khalid International Airport in Riyadh, Saudi Arabia, prompting the suspension of airport operations and renewed threats of military retaliation against Yemen’s Houthi rebels.

Saudi authorities said the casualties included four Saudi nationals, two Bangladeshis and one citizen each from the United States, Jordan, Palestine, Syria, Sudan and Egypt. Some of the injured were reported to be in critical condition.

The Saudi-led military coalition blamed the Iran-backed Houthis for the attack, describing it as a war crime after a strike hit a passenger terminal and caused casualties among travellers and airport staff. The Houthis had not immediately claimed responsibility for Saturday’s incident, although they acknowledged carrying out strikes on the same airport on Thursday that killed three people and damaged an aircraft.

Following the latest attack, airport operations were suspended as authorities assessed the damage. Emergency services deployed ambulances to the scene, while medical personnel were mobilised to treat the injured. Reports also indicated that some pilgrims travelling to Mecca were among those affected.

The Saudi-led coalition said it had intercepted missiles targeting the kingdom and destroyed launch platforms. Coalition spokesperson Major General Turki al-Maliki condemned the airport strike and warned of a response, as concerns mounted over the escalation of attacks on Saudi territory.

The United States also signalled the possibility of becoming more directly involved. President Donald Trump said Washington could join Saudi Arabia in military action against the Houthis, describing the attack as unacceptable and indicating that he planned to speak with Saudi Crown Prince Mohammed bin Salman.

The latest violence follows the breakdown of a truce in Yemen’s long-running civil war and a renewed campaign of Houthi attacks on Saudi airports, oil facilities and vessels in the Red Sea. Saudi Arabia has supported Yemen’s internationally recognised government in its conflict with the Houthis since 2015.

The confrontation has also spread towards the Bab al-Mandab Strait, a strategic maritime chokepoint linking the Red Sea to the Gulf of Aden and a major route for global shipping. Saudi-backed Yemeni government forces have launched operations to regain territory held by the Houthis in the area, adding to concerns about regional security and disruptions to commercial transport.

The airport attack drew condemnation from several governments and international officials. United Nations Secretary-General António Guterres called for the attacks to stop, describing them as violations of international law. Western embassies in Saudi Arabia also advised their citizens to avoid the airport, while some airlines cancelled services because of the security situation.

The latest strike was described in reports as the deadliest attack on Saudi soil since May 2015. With airport operations disrupted and the prospect of further military action looming, the incident has intensified fears that the conflict could widen across the region.