LONDON — Iran seized a British oil tanker in the Persian Gulf on Friday, the latest confrontation in three months of escalating tensions between Iran and the West.

Britain’s foreign secretary, Jeremy Hunt, said Iranian authorities had also seized another tanker, adding that he was “extremely concerned” and that British officials were working “to swiftly secure the release of the two vessels.”

But Iran quickly disputed that account, saying the second tanker “was not seized,” according to Fars, the nation’s semiofficial news agency.

Instead, it said, the second ship “was given a warning by Iran’s armed forces about observing environment regulations and safety precautions and it went on its way.”


The ship’s manager, Norbulk Shipping UK, said in a statement that the vessel “was boarded by armed personnel” Friday, but it was released and allowed to continue its voyage. No one was injured, it said.

Hunt said the Iranian actions were “unacceptable,” adding, “It is essential that freedom of navigation is maintained and that all ships can move safely and freely in the region.”

He said the British ambassador to Iran had been in communication with the Iranian Foreign Ministry.

The seizure came a day after the United States said it had downed an Iranian drone in the area, which the Iranians denied, and after weeks of dispute between Britain and Iran over Britain’s seizure of an Iranian tanker near Gibraltar. Iran had vowed to retaliate.

Iran’s Fars News Agency said the seized ship, the Stena Impero, had been impounded because it was “violating maritime rules and regulations.” Tasnim, an official Iranian news agency, reported that the tanker had turned off its GPS locator, was polluting the waters of the Persian Gulf, and had tried to enter the Strait of Hormuz in an area where most ships exit, creating the risk of an accident.


The ship’s owners issued a statement that the Stena Impero, which was heading for Saudi Arabia when it abruptly left international sea lanes, had been “approached by unidentified small crafts and a helicopter during transit of the Strait of Hormuz while the vessel was in international waters.”

“We are presently unable to contact the vessel which is now heading north toward Iran,” the owners, Stena Bulk, and the ship’s managers, Northern Marine, said in the statement.

The United States’ most senior military intelligence officer, Lieutenant General Robert P. Ashley Jr., said Friday that Iran was seeking to find an equivalent response to the seizure of an Iranian tanker by Britain this month.

“They look for things that are proportional in nature,” Ashley told reporters at the Aspen Security Forum in Colorado. “They aren’t looking to go to war but at the same time they are looking to project strength.”

Earlier Friday, Iranian officials denied that the US military had downed an Iranian drone in the Strait of Hormuz, a day after President Trump and Pentagon officials first made that announcement.

A spokesman for the Iranian Armed Forces said the “unfounded claim” had been intended to increase tensions in the Persian Gulf, according to Tasnim.

The Strait of Hormuz has been the focal point of increasing tensions between Iran and the United States in recent months, after a series of incidents in the waterway, a narrow stretch through which a fifth of the world’s supply of oil flows.


Six tankers were damaged in May and June in the Gulf of Oman. The United States described the incidents as attacks by Iran, though Tehran denied any role.

On Thursday, Iranian media reported that Iran’s Revolutionary Guard had detained a foreign oil tanker in the Strait of Hormuz. The Revolutionary Guard said the vessel had been smuggling fuel, just days after a United Arab Emirates vessel with the same name disappeared in the Persian Gulf.

Relations between Iran and the United States have been deteriorating since last year, when Trump pulled the United States out of the landmark 2015 nuclear accord and began imposing a series of punishing economic sanctions on Tehran.

The 2015 agreement had limited Iran’s nuclear development in exchange for economic relief. With the new sanctions battering Iran’s economy, Tehran set deadlines for the European signers of the deal to come up with a strategy to ease their impact.

Since early July, Iran has begun slowly reducing its compliance with the accord.