The Ministry of Defence has said Iranian boats tried to impede a British oil tanker near the Gulf before being driven off by a Royal Navy ship.
HMS Montrose, a British frigate escorting the tanker British Heritage, was forced to move between the three boats and the tanker, a spokesman said.
He described the Iranians’ actions as “contrary to international law”.
Iran had threatened to retaliate for the seizure of one of its own tankers, but denied any attempted seizure of a British boat. Boats believed to belong to Iran’s Islamic Revolution Guard Corps approached British Heritage and tried to bring it to a halt as it was moving out of the Gulf into the Strait of Hormuz.
Guns on HMS Montrose were trained on the Iranian boats as they were ordered to back off. The boats heeded the warning and no shots were fired, and British Heritage was near the island of Abu Musa when it was approached and harassed by the Iranian boats.
The island of Abu Musa is disputed in local territorial waters, but HMS Montrose stayed in international waters throughout.
A UK government spokesman said: “Contrary to international law, three Iranian vessels attempted to impede the passage of a commercial vessel, British Heritage, through the Strait of Hormuz. “We are concerned by this action and continue to urge the Iranian authorities to de-escalate the situation in the region.”
In a tweet, the IRGC “denies claims by American sources” that it tried to seize British Heritage.
“There has been no confrontation in the last 24 hours with any foreign vessels, including British ones,” the IRGC added, according to the AFP news agency. Iranian foreign minister Mohammad Javad Zarif said the UK made the claims “for creating tension”. “These claims have no value,” Mr Zarif added, according to Fars.
Tensions are still rising between the UK, US and Iran, with Iran continuing to deny claims against them.
