DUBAI, United Arab Emirates – When Pentagon officials announced plans to send U.S. Navy minesweepers and warships into the Gulf for exercises, they carefully tried to avoid framing it as a direct show of force against Iran. Tehran took care of that.

Iranian commanders and political leaders – facing an increasing squeeze from international sanctions – have sharply stepped up threats and defiant statements in recent weeks over the Strait of Hormuz, a chokepoint at the mouth of the Gulf that is the route for one fifth of the world's oil.

While it appears unlikely that Iran is ready to risk an almost certain military backlash by trying to close Hormuz – which is jointly controlled with Oman – the latest flurry from Tehran shows that Iranian authorities see the strait as perhaps their most valuable asset in brinksmanship over tightening sanctions and efforts to resume nuclear talks with world powers.