BEIRUT, Lebanon — Iran has seized a foreign oil tanker in the Persian Gulf that it said was “smuggling” fuel to some Arab states, state television reported on Sunday, the third time that Tehran has reported detaining an oil tanker in the past month as the United States has applied a campaign of “maximum pressure,” sanctions and diplomatic isolation.
The tanker was detained by the country’s Islamic Revolutionary Guards Corps on Wednesday, along with the seven members of the ship’s foreign crew, according to official Iranian news agencies, which cited a naval commander.
The Trump administration has tried to force Iran into submission by choking off its oil sales, the cornerstone of the country’s economy. Iran has responded by lashing out at the West through provocations small and large — including the recent tanker seizures — raising fears that any miscalculation and tit-for-tat responses would escalate into war.
The Trump administration’s stated goal is to extract a nuclear deal from Iran that is more favorable to American interests than the 2015 agreement that President Trump abandoned last year. Critics say, however, the administration has only undermined any path to diplomacy by making demands that Iran cannot accept.
The Iranians, in turn, have taken steps to renege on their commitments under the 2015 deal and have threatened to violate the agreement further unless European countries that co-signed the deal offer some relief from the sanctions. The Europeans have made clear that they hope to preserve the deal, but they have not been able to give a meaningful boost to Iran’s economy, which is reeling under the weight of the sanctions.
That has led to a split between Europe and the United States despite their common interest in making sure crucial oil shipping routes in the Persian are protected against Iranian and other threats. The Trump administration has sought to rally a maritime force to escort ships through the Gulf, but European nations have distanced themselves from the effort, and Germany has outright said no.
The latest foreign vessel Iran said it had seized received fuel from other ships and had been transporting it to Arab countries in the Persian Gulf, the commander of Iran’s Second Marine Corps said in a statement to the Fars News Agency. The ship was detained in coordination with judicial authorities, he said.
The commander said the ship had been carrying about 700,000 liters of fuel, about 185,000 United States standard gallons. The semiofficial Iranian news agency Fars said on Twitter that “seven foreign nationals” had been detained. The news agency Mehr reported that the ship had been seized near Farsi Island, a tiny, barren Iranian territory northwest of the Strait of Hormuz.
A Revolutionary Guards statement said the ship had been seized to the south of the Iranian island of Larak, in the northern part of the Strait of Hormuz, the narrow waterway that is a vital conduit for maritime petroleum traffic in and out of the Persian Gulf.
The oil tanker was then transferred to Bushehr Province, the statement said, and its cargo delivered to the department of the National Iranian Oil Product Distribution Company in the same province, Mehr reported. No further details were provided, including who owns the vessel and the nationalities of the seized crew members.
In July, the Islamic Revolutionary Guards Corps detained a foreign oil tanker said to have been smuggling fuel, state news media reported.
The latest seizure was reported days after the United States imposed sanctions on the Iranian foreign minister, Mohammad Javad Zarif, an American-educated diplomat who was a key negotiator for the 2015 nuclear deal between Western powers and Tehran. American officials have said that the foreign minister is part of a “propaganda arm” for Iran. But experts said the sanctions would make it more difficult to engage in any new diplomacy. Iranian officials called the move petty and provocative.
Iran and the West has been embroiled in a dispute over shipping near the Strait of Hormuz as European countries scramble to save the 2015 nuclear deal with Iran after Mr. Trump pulled the United States out of the accord last year.
Britain seized an Iranian tanker, the Grace 1, off the coast of Gibraltar in July, saying it suspected the ship had been headed to Syria in violation of European Union sanctions. Iran called the seizure an act of piracy, and accused Britain of acting on behalf of Washington.
Later that month, Revolutionary Guards troops also detained a British-flagged tanker, the Stena Impero, near the Strait of Hormuz, accusing it of violating “three international naval regulations.”
Iran appeared to link the British seizure of its tanker and the ailing nuclear deal. “Since Iran is entitled to export its oil according to the J.C.P.O.A., any impediment in the way of Iran’s export of oil is actually against the J.C.P.O.A.,” Iran’s deputy foreign minister, Abbas Araghchi, said after emergency talks in Vienna a week ago.
That day, a second British Royal Navy warship, the Duncan, arrived in the Persian Gulf to escort ships flying the British flag through the Strait of Hormuz. Iran has warned other countries against sending vessels to act as escorts, with a government spokesman in Tehran, Ali Rabiei, saying that such a move would carry “a hostile message, is provocative and will increase tensions.”
On May 2, the Trump administration’s oil sanctions against Iran came into full effect. It is not illegal under international law to buy and haul Iranian oil or related products, but foreign companies that ignore the sanctions risk being punished by the United States.
An examination of the movements of more than 70 Iranian tankers since May 2 found that 12 had loaded oil after that date and had delivered it to China or the eastern Mediterranean, where the buyers might have included Syria or Turkey. Only some of the 12 tankers were previously known to have recently delivered Iranian oil.
The continued flow of oil highlights the difficulty that the Trump administration has had in using sanctions to bring Iranian oil exports to zero.