Last month Iran threatened to close the Strait of Hormuz along which 20 per cent of all oil is traded in retaliation for tighter Western sanctions.
But America's military might is in full display as its aircraft carrier USS Abraham Lincoln sails through the Strait for the second time in month.
Despite America's insistence that it is a routine voyage, BBC's Jonathan Beale reports it is sending a clear message that it is patrolling the troubled waters.

