Iran attacked a cargo ship traveling through the Strait of Hormuz on Thursday, possibly upending President Donald Trump‘s diplomatic end to the war with Iran.

A U.S. official confirmed to the Washington Examiner that the Islamic Revolutionary Guard Corps “struck it with a drone.” The U.K. Maritime Trade Operations reported the attack Thursday afternoon, writing that “a cargo vessel has been hit on the starboard side by an unknown projectile, causing damage to the bridge,” but no casualties.