Iranian Navy missile launch during a military drill in the Gulf of Oman (Picture: Iranian Navy handout).
Iran launched a cruise missile from a submarine for the first time in the Strait of Hormuz, state media has reported.
The Iranian navy is currently holding Velayat 97, a three-day annual military drill, involving a 100 vessels off the country's southern coast.
The Strait of Hormuz, at the mouth of the Persian Gulf, is a crucial bottleneck for global energy supplies.
About a third of all oil traded by sea passes through the strait.
Tensions have risen since the US withdrew from Iran's 2015 nuclear agreement with world powers last year and restored wide-ranging sanctions.
The semi-official Fars news reported on the missile launch and said other submarines have the same capability.
No details were provided on the missile's range.
Admiral Hamzeh Ali Kaviani, spokesman for the drills, said:
"By achieving various types of sub-surface missile and torpedoes, we have completed our chain of defensive power under water".
Iranian media said the missile was an upgraded version of the Nasr-1 missile the country had showcased in 2008.
It was then described as an anti-vessel missile with a range of 22 miles.
Iran frequently touts its military arsenal, much of which is manufactured locally because of international sanctions.