Iran Says British Tanker Is Free to Go After 2 Months of Detention

A British-flagged tanker that Iran seized in July is now free to leave, Tehran said on Monday, more than a month after the British authorities released an Iranian tanker that had been detained off Gibraltar.

The news offered a rare sign of comity at a time when Iran has been in an escalating cycle of confrontation with its Persian Gulf neighbors and with the United States, including the shooting down of drones, the seizure of tankers and, most recently, an attack on major oil installations in Saudi Arabia.

Officials of the United States and Saudi Arabia, Iran’s chief rival in the region, have blamed Tehran for the Sept. 14 attack on oil centers in the kingdom, raising the prospect of retaliatory strikes and even war. But so far, the only apparent action they have taken against Tehran is a tightening of economic sanctions.

Iran had accused the British-flagged tanker, the Stena Impero, of violating maritime regulations in the Strait of Hormuz, but the seizure on July 19 was widely seen as retaliation for the detention of the Iranian vessel.

The legal proceedings against the Stena Impero have concluded, and Iran has decided to waive the allegations of violations, an Iranian government spokesman, Ali Rabiyee, said at a news conference, according to Iranian and Western news agencies that were present.

The ship had not left Bandar Abbas, a port in southern Iran, as of midday, and it was not clear how quickly it would set sail. Erik Hanell, chief executive of the tanker’s owner, the shipping company Stena Bulk, told SVT, a Swedish television station, that he hoped it would be a matter of hours.

Iran detained the 23-member crew along with the ship. It released seven of them this month, but the others have remained with the vessel.

The decision to release the ship comes a little more than a week after the attack on the Saudi oil installations. Iran has denied any responsibility for the attack, a sophisticated operation involving some two dozen drones and cruise missiles. The aerial strikes damaged infrastructure and temporarily cut Saudi oil production in half, sending tremors through world markets, but they caused no reported casualties.

The Houthi rebel faction in Yemen’s civil war, a group that is known to use weapons supplied by Iran, has said it carried out the attack against Saudi Arabia, which has been bombing in Yemen for more than four years, killing thousands of people.

Prime Minister Boris Johnson of Britain said early on Monday that there was “a very high degree of probability” that Iran was responsible for the strikes in Saudi Arabia, and he did not rule out British participation in military retaliation. The topic is sure to be aired this week at the United Nations General Assembly’s annual gathering of heads of government, which will be attended by Mr. Johnson, President Trump and President Hassan Rouhani of Iran, among many others.

In May and June, several tankers operating near the Strait of Hormuz were damaged in what the United States said was sabotage by Iranian forces — which Iran also denied. Iran also detained several ships for varying periods of time, notably the Stena Impero, and shot down an American surveillance drone.

Analysts have characterized the attacks — whether carried out by Iran or by one of the armed factions it supports in the Middle East — and ship seizures as Tehran’s demonstration that it has the power to cut off a large part of the world’s energy supplies.

Iran wants relief from punishing sanctions imposed by President Trump since he withdrew the United States from a 2015 deal that restricted the Middle Eastern country’s nuclear program. Relations have grown worse since then, as the United States has steadily added more economic penalties, seeking to choke off Iran’s oil sales, the life blood of its economy. In recent months, Iran has taken a series of steps to go beyond the limits imposed by the nuclear accord.

While many other nations, including key American allies, have sided with Iran on the nuclear deal and the sanctions, there is less sympathy for Iran internationally than there was before the recent provocations.

The direct confrontation with Britain began on July 4, when British marines and Gibraltar port officials seized an Iranian tanker, Grace 1, which has since been renamed the Adrian Darya 1. They said the ship was carrying oil to Syria, in violation of a European Union embargo.

Iran denied the allegation and accused the British of concocting the story to act against Tehran at the behest of Washington, though Britain formally opposes the American sanctions.

The government of Gibraltar, a semiautonomous British territory, released the ship six weeks later, and said that it had assurances that the Iranian tanker would not go to Syria. American officials asked that the ship be turned over to them, but the Gibraltar government rejected the request.