The combined missile and drone attack amounted to one of the most serious breaches of American air defenses in the course of the monthlong war with Iran.

An Iranian strike injured 12 U.S. troops in Saudi Arabia, two of them seriously, in an attack on Prince Sultan Air Base in Saudi Arabia, two U.S. officials, who were not authorized to speak publicly, said on Friday.

The combined missile and drone attack amounted to one of the most serious breaches of American air defenses in the course of the monthlong war with Iran. At least two KC-135 aerial refueling planes also suffered significant damage in the attack.

The strike comes as Trump has vacillated between promising peace and escalating strikes aimed at critical civilian infrastructure. The president has said that peace talks are underway, and going well — a claim that Iranian officials have disputed — even as more warships and thousands of troops have been deployed to reinforce U.S. forces in the region.