Iran threatens U.S. Navy as sanctions hit economy | Reuters

Iran threatens U.S. Navy as sanctions hit economy | Reuters: (Reuters) - "Iran threatened Tuesday to take action if the U.S. Navy moves an aircraft carrier into the Gulf, Tehran's most aggressive statement yet after weeks of saber-rattling as new U.S. and EU financial sanctions take a toll on its economy."

If the US Navy moves an aircraft carrier into the Gulf, who is aggressing whom?