Iran seized two UK-linked tankers in the Strait of Hormuz on Friday, sharply escalating tensions in one of the world’s most important oil shipping lanes at a time militaries in the region have been on a hair trigger.
The Iranian Revolutionary Guards said the UK-flagged Stena Impero was “seized by the guards’ naval forces” as it moved through the key Gulf waterway. Tehran insisted the tanker had “failed to observe the international maritime rules and regulations”.
A second, Liberian-registered vessel — the Mesdar — was also “boarded by armed personnel”, according to the tanker’s British ship manager, Glasgow-based Norbulk Shipping. But late on Friday Norbulk said communications had been re-established and the ship was now “free to continue the voyage”. All crew were reported safe.
The seizures come 24 hours after the US claimed to have shot down an Iranian drone that ventured too close to an American warship in the strait.
Tehran has denied it lost a drone, but the incident is a sign of how naval deployments aimed at protecting tankers transiting the strait are raising the threat of military conflict. The USS Boxer was part of an American flotilla tasked with securing the shipping lanes when it fired on the drone.
One UK official said HMS Montrose, a Royal Navy frigate, had tried to come to the aid of the Stena Impero but arrived too late. Last week, the UK warship intervened to prevent Iranian forces impeding the passage of a tanker owned by the British energy group BP as it moved through the Gulf.
A spokesman for the US National Security Council noted that Friday’s seizure was “the second time in just over a week the UK has been the target of escalatory violence by the Iranian regime”.
Washington and London have previously blamed Iran for sabotage attacks on six tankers off the coast of the United Arab Emirates in May and June.
Jeremy Hunt, the UK foreign secretary, called the seizure “unacceptable” and vowed to get the ships released. Although there were “a range of nationalities” on the vessels, Mr Hunt said none were British citizens.
“It is essential that freedom of navigation is maintained and that all ships can move safely and freely in the region,” Mr Hunt said.
Tehran has repeatedly threatened to retaliate against the UK for Britain’s decision to seize an Iranian tanker suspected of smuggling oil to Syria in violation of EU sanctions this month.
Stena Bulk, the owner of the Stena Impero, said the tanker was approached by “unidentified small crafts and a helicopter” as it was in the strait en route to Saudi Arabia. The Swedish company said it was unable to contact the ship, which has a crew of 23.
The UK government’s Cobra emergency response committee was convened on Friday evening to discuss London’s options. Britain is only days away from having a new prime minister, with Theresa May due to step down when the Conservative party announces a new leader on Tuesday.
Speaking at the White House, Donald Trump said he would be in contact with the British government to discuss how to respond. “This only goes to show what I’m saying about Iran: trouble. Nothing but trouble,” the US president said.
The Saudi defence ministry said on Friday that King Salman had approved hosting US troops in the kingdom “to increase joint co-operation in defence of regional security and stability and to preserve its peace”.
On Friday night the US military confirmed that more American personnel and resources would be sent to Saudi Arabia.
“This movement of forces provides an additional deterrent, and ensures our ability to defend our forces and interests in the region from emergent, credible threats,” said a statement from the defence department’s US Central Command.
It said the deployment would improve “operational depth and logistical networks” in the kingdom and US assets would be based “at the appropriate locations”.
Last month Mr Trump aborted strikes on Iran 10 minutes before they were to be launched after Iranian forces downed an unmanned American spy drone.
Ship tracking data showed the Stena Impero to be sailing on Friday towards the Jubail refinery in Saudi Arabia, where it was expected to load petrochemical products on July 21.
The vessel then made an abrupt turn after 3pm UK time moving towards the port of Bandar Abbas in Iran, energy data company Kpler said, adding that the vessel appeared to have turned off its tracker. Kpler said it expected “the Stena Impero to remain dark as she approaches the Iranian coastline as the Iranian forces will most likely try to mask her final destination”.
The Revolutionary Guards said the Stena Impero had been handed over to Iran’s state-run Ports and Maritime Organisation.
Brent crude, the international oil benchmark, rose sharply after the seizures were made public by 2.1 per cent to $63.23 a barrel.
The tanker’s seizure puts the UK and Iran on a collision course at a time when Britain has been working with other European countries to de-escalate tensions.
The crisis in the Gulf was triggered by Mr Trump’s decision to unilaterally withdraw the US from the 2015 nuclear accord Iran signed with world powers. Crippling US sanctions have pushed Iran into a deep recession and thwarted its ability to export oil — the republic’s economic lifeline.
Iranian officials have warned that if they are not able to export crude, Tehran will disrupt oil and petrochemical traffic through the Strait of Hormuz — through which about a third of seaborne oil travels.
In May Washington dispatched an aircraft carrier strike group to the Gulf citing unspecified “escalatory” activity by Iran. In the weeks since there have been several incidents in the region amid warnings that the increased tensions could lead to a “miscalculation” sparking a wider conflagration.
The UK has not supported the US decision to pull out of the nuclear accord and impose sanctions on Iran. It has been working with France and Germany, the other European signatories to the nuclear deal, to save the deal and help Iran counter the economic impact of Washington’s punitive measures.
But Britain’s role has been complicated by its decision to apprehend the Iranian tanker off the coast of Gibraltar this month. UK officials insisted they had no choice because the vessel was in European waters and suspected of violating the EU sanctions.
HMS Montrose is the only large UK warship in the Gulf, although the Royal Navy also operates four minesweepers in the area. A second British warship, the destroyer HMS Duncan, is on its way to the region to offer additional protection to UK shipping interests.
Additional reporting by Aime Williams in Washington, Ahmed Alomran in Riyadh and David Bond, Jim Pickard and Anjli Raval in London