WASHINGTON/LONDON/DUBAI - U.S. President Donald Trump warned Tehran on Wednesday that sanctions would soon be “increased substantially,” as armed Iranian boats reportedly attempted to block a British oil tanker in Persian Gulf waters.
The British government said its navy intervened to stop Iran from preventing a commercial oil tanker from leaving the Gulf, heightening friction just as European nations scramble to salvage a landmark nuclear accord.
The BP PLC-operated British Heritage, which can carry as much as 1 million barrels of oil, was attempting to pass through the Strait of Hormuz, a shipping chokepoint at the mouth of the world’s largest oil-producing region, when three Iranian vessels tried to block it, according to a U.K. government statement.
The incident comes after U.K. forces seized a tanker off Gibraltar earlier this month that was suspected of carrying Iranian oil to Syria. Iran denied the vessel was heading to Syria and vowed to retaliate, but the seizure opened up a wrangle that could drag on for months and complicate efforts to contain a brewing crisis over Iran’s compliance with a 2015 deal meant to prevent it from developing a nuclear weapon.
The Royal Navy’s HMS Montrose, which was escorting the tanker, “was forced to position herself between the Iranian vessels and British Heritage and issue verbal warnings to the Iranian vessels, which then turned away.”
“We are concerned by this action and continue to urge the Iranian authorities to de-escalate the situation in the region,” the statement said.
The British Heritage was able to pass through the Strait of Hormuz and was now sailing along the Omani coast, according to tanker tracking data compiled by Bloomberg.
But Thursday’s developments also highlight the mounting risks to shipping in a region that exports about a third of all seaborne petroleum.
BP had been keeping the British Heritage empty inside the Gulf, near Saudi Arabia, rather than risk its seizure by Iran, a person familiar with the matter said Monday. Six tankers have been attacked since early May, with the U.S. blaming Iran for the incidents, a charge Tehran denies.
Iran’s Revolutionary Guard Corps denied trying to impede the British tanker but said it could act fast if it was ordered to do so. “If it receives an order to seize foreign ships, naval forces can act fast, with determination and without hesitation within the geographic scope of its mission,” the semiofficial Fars news agency reported.
Tensions in the Gulf have soared since the U.S. quit the multiparty nuclear accord with Iran a year ago and re-imposed sanctions on the Islamic Republic. In early May, the U.S. tightened penalties on buyers of Iranian oil prompting Iran to begin scaling back its commitments under the deal.
Trump’s sanctions warning — which he delivered via Twitter — came as French President Emmanuel Macron’s top diplomatic adviser met with Iran’s president, winding up a day of talks in Tehran aimed at saving the landmark 2015 nuclear deal.
Emmanuel Bonne met Foreign Minister Mohammad Javad Zarif and Ali Shamkhani, secretary of Iran’s Supreme National Security Council.
French officials say they see room for compromise, as Iran’s infringements have been carefully calibrated. Iran’s dialogue with Europe never stopped but it said it won’t speak to the U.S. unless sanctions are eased first.
The 2015 accord between Iran and world powers promised sanctions relief, economic benefits and an end to international isolation in return for stringent curbs on the Islamic republic’s nuclear program.
Tehran says it has lost patience with perceived inaction by European countries more than a year after Trump unilaterally pulled the U.S. out of the agreement and started to impose the punishing sanctions.
Iran said this week it’s enriching uranium beyond the agreed cap and would gradually roll back compliance unless European signatories find ways to ensure it can sell its oil and access the global financial system.
Iran is producing oil at the slowest clip since 1986, making U.S. sanctions as effective as the devastating Iraq-Iran war that ended more than 30 years ago. The measures have hit the currency, fueled inflation and hobbled growth.