WASHINGTON — U.S. Defense Secretary Pete Hegseth claimed Wednesday that "America is winning" in an ongoing military operation against Iran, as he announced a U.S. submarine sunk an Iranian warship with a torpedo in the Indian Ocean the previous day. Hegseth and Joint Chiefs of Staff Chairman Gen. Dan Caine held a press briefing on progress in the operation, codenamed "Operation Epic Fury," including the U.S. military having killed the leader of an Iranian unit that attempted to assassinate President Donald Trump. "I stand before you today with one unmistakable message about Operation Epic Fury: America is winning decisively, devastatingly and without mercy under the direct command of President Trump," Hegseth said. Noting the military operation against Iran kicked off just on Saturday, the Pentagon chief said the United States will "take all the time we need to make sure that we succeed." "We can sustain this fight easily for as long as we need to," he said. Hegseth highlighted the headway that the U.S. military is making in the operation, including the sinking of the Iranian vessel. "An