Iranian President Hassan Rohani has again threatened to close a key passageway for oil trade if the U.S. blocks oil exports.<br />The Strait of Hormuz is the waterway for nearly a third of all oil traded by sea. <br />Rohani has threatened to close the sea lane several times before, but he is yet to follow up on those threats.<br />The Trump administration restored sanctions on Iran's energy industry to try and pressure Tehran to give up its nuclear and missile tests. <br />
