President Donald Trump said the United States may join Saudi Arabia’s response to an attack on Riyadh’s main airport, but no decision has been announced. Asked on Saturday about backing Saudi strikes against Iran-backed Houthi militants in Yemen, he said the administration would consider it.

Saudi Arabia’s civil aviation authority said the attack on King Khalid International Airport killed 12 people and injured 309. It was the second deadly assault on the airport in less than a week; three Saudi nationals, including a pilot, were killed in an attack on Thursday.

Two Saudi government officials said the kingdom was seeking urgent U.S. defense support for the Saudi-led coalition fighting the Houthis in Yemen. Coalition spokesman Colonel Turki Al-Maliki said its forces would respond to the latest attack. Analysts said U.S. involvement could strain military resources already committed to fighting Iran in the Middle East.