U.S. President Donald Trump said the U.S. Navy fired upon and seized an Iranian-flagged cargo ship in the Gulf of Oman after it failed to heed warnings to stop as it left the Strait of Hormuz, the first major encounter in the week-old blockade.Trump said in a social media post that the ship, the Touska, “tried to get past our Naval Blockade, and it did not go well for them.”U.S. Central Command, which oversees military operations in the Middle East, issued a statement saying that the Touska failed for six hours to comply with warnings to stop. The Navy ordered the ship to evacuate its engine room before firing several rounds from a 5-inch MK45 gun into the engine room to disable the ship. U.S. Marines boarded the vessel and took control, Centcom said.