Iranian naval patrols have reportedly stopped and searched French and Italian ships during military exercises in the Strait of Hormuz.
The official Iranian news agency says detachments of the Revolutionary Guards inspected the two European vessels for compliance with environmental regulations.
It says they were allowed to go when no breaches were found.
The Strait of Hormuz is a key shipping route. About 40% of the world's oil leaves the Gulf region through the seaway.