Iran has released a video of its forces warning Royal Navy warship HMS Montrose that the lives of its crew could be in danger.
The exchanges between Iranian Revolutionary Guard officers and the British frigate were released by Tehran as a second Royal Navy warship arrived in the region to protect British ships.
Tensions between the UK and Iran have been heightened following the seizure of British-flagged tanker Stena Impero on July 19.
The Ministry of Defence said Royal Navy destroyer HMS Duncan has reached the Gulf to join Montrose in escorting merchant vessels.
The video released by Tehran includes a shot purportedly filmed on the day of the July 19 incident from above HMS Montrose in an attempt to show the Royal Navy was unable to prevent Iran seizing the Stena Impero.
In the nearly two-minute video released by the Iranian Guard, an officer is heard telling the Montrose: “You are ordered to not interfere in my operation.”
The Iranian officer repeats: “You are required not to interfere in this issue.”
An officer on board the Montrose, whose pennant number is F236, said: “This is British warship Foxtrot 236.
“I am in vicinity of the internationally recognised strait with a merchant vessel in my vicinity conducting transit passage.”
The Iranian officer is then heard saying: “Don’t put your life in danger.”
He said the tanker was now under Iranian control.
The Government has announced that British-flagged ships travelling in the Strait of Hormuz will be accompanied by a Royal Navy escort, with officials advising shipping companies to travel in convoy.
HMS Montrose has so far escorted 35 shipping vessels through the troubled strait during 20 separate journeys.
The Ministry of Defence stressed the importance of freedom of navigation for global trade and economies.
Defence Secretary Ben Wallace said: “Freedom of navigation in the Strait of Hormuz is vital not just to the UK but also our international partners and allies. Merchant ships must be free to travel lawfully and trade safely anywhere in the world.
“I’m pleased that HMS Duncan will continue HMS Montrose’s fine work in helping to secure this essential route.
“While we continue to push for a diplomatic resolution that will make this possible again without military accompaniment, the Royal Navy will continue to provide a safeguard for UK vessels until this is the reality.”