Iranian forces boarded a Marshall Islands-flagged cargo ship in the Gulf on Tuesday after patrol boats fired warning shots across its bow and ordered it deeper into Iranian waters as it was traveling through the Strait of Hormuz, the Pentagon said. The ship, the MV Maersk Tigris, initially ignored Iranian patrol boats that ordered it deeper into Iranian territorial waters but complied after the vessels fired several warning shots, U.S. Army Colonel Steve Warren said. U.S. forces in the region responded to distress calls from the Maersk Tigris, sending the destroyer USS Farragut to monitor the situation along with reconnaissance aircraft. No U.S. citizens were aboard the cargo ship, Warren said.