Iranian navy soldiers take part in a military exercise in the Strait of Homruz on Wednesday Tensions between the United States and Iran have dangerously ratcheted up as naval officials with America's Fifth Fleet warned any attempt by Iran to close a strategically vital oil route through the Strait of Hormuz would "not be tolerated". The news heightens a sense of growing crisis in the Persian Gulf after two days of threats by senior Iranian figures that they might shut down the important trade route in response to any future international sanctions against the country's oil exports. "Anyone who threatens...