Gibraltar Chief Minister Fabian Picardo said the US was still on time to request a new legal procedure for seizing the Grace 1, but that provisions under the European Union’s sanctions regulations were ending on Thursday after the Iranian government assured him in writing that the ship will not send its 2.1 million barrels of crude to a sanctioned entity in Syria.

Reacting to the developments, Iran’s Foreign Minister Mohammad Javad Zarif accused the US of trying to “steal our property on the high seas”.

“Having failed to accomplish its objectives through its #EconomicTerrorism – including depriving cancer patients of medicine – the US attempted to abuse the legal system to steal our property on the high seas,” Zarif tweeted, calling the Trump administration’s moves a “piracy attempt”.

It was not clear whether the Grace 1 would sail away immediately; nor was it known what the Trump’s administration strategy was. The US Justice Department did not respond to requests for comment.

“This is an important material change in the destination of the vessel and the beneficiary of its cargo,” Gibraltar’s Picardo said in a statement, adding that the move ensured that the Syrian government of President Bashar al-Assad would be deprived of more than US$140 million of crude oil.

Britain holds crisis talks over Iran’s seizure of tanker

Gibraltar said it had “solid documentary evidence” that the vessel was bound for Syria when it was detained on July 4, but that the political fallout had prompted talks with Iranian officials in London.

Picardo’s office released copies of communications with the Syrian Embassy in Britain soon after the British overseas territory’s Supreme Court decision to release the tanker.

The court had delayed its decision after the Justice Department made a last-minute application to extend the detention of the oil tanker, the Gibraltar government had said earlier Thursday. But there was no US application to the court when the hearing resumed in the afternoon, the Gibraltar Chronicle newspaper reported, quoting the court’s chief justice, Anthony Dudley.

Picardo said that any US request to detain the Grace 1 would now to be examined under bilateral agreements and outside of the EU sanction mechanism.

The EU has endorsed UN sanctions against Syria and has imposed a broad range of its own restrictions against Assad’s government and its supporters. The restrictions include an oil embargo, limits on certain type of investments and a freeze of Syria’s central bank’s assets in the EU, among others.

In May, it extended until mid-2020 travel bans and the freezing of assets of 269 individuals and 69 entities. Among them is listed the Banyas refinery where the Grace 1’s cargo was allegedly headed on July 4 when it was seized in a British Royal Navy operation in the Strait of Gibraltar.

Soon after that, Iran seized the British-flagged oil tanker Stena Impero, which remains held by the Islamic Republic. Analysts had said the release of the Grace 1 by Gibraltar could see the Stena Impero go free.

On Thursday, Britain’s Foreign Office said in a statement that the “investigations conducted around the Grace 1 are a matter for the government of Gibraltar”, and that it could not comment further.

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British Prime Minister Boris Johnson’s Downing Street office said Iran was discussed during his meeting with Trump’s national security adviser John Bolton earlier in the week, though no details were released.

Signalling preparations for the expected release of the ship, the captain, an Indian national, and three officers of the Grace 1 were released from detention, the Gibraltar government said.

The whereabouts of the crew, none of whom are Iranian, were not immediately known. The crew of the Grace 1 includes sailors from India, Pakistan and Ukraine, according to Iranian state television.

Beyond a few Gibraltar-flagged patrol boats, an Associated Press crew saw little security around the tanker on Thursday. A handful of men could be seen on the deck, some looking through binoculars.

This is the second time the Trump administration has moved to seize a ship in recent months. In May, the Justice Department said it had seized a North Korean cargo ship used to supply coal to the isolated nation in violation of international sanctions.

Tensions have escalated in the Persian Gulf region since Trump unilaterally withdrew the 2015 nuclear deal signed by Iran, Britain, France, Germany, Russia and China. The decision stopped billions of dollars in business deals, largely halted the sale of Iran’s crude oil internationally and sharply depreciated Iran’s currency, the rial.

In recent weeks, Iran has begun to step away from the deal by increasing its production and enrichment of uranium. It has threatened to take further steps in early September if Europe cannot help it sell its oil abroad.

Lina Khatib, head of the Middle East and North Africa programme at Chatham House, said the US request on the Grace 1 was based on its own imposed sanctions on Iran, and not the EU’s sanctions on oil exports to Syria.

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“Although the US expects its European allies to abide by these sanctions, it is up to the Gibraltar authorities to assess the allegations presented by the US,” Khatib said.

Resolving the tanker dispute would help Britain’s Johnson focus on domestic issues as he works to complete Britain’s exit from the EU and prepare for anticipated national elections in the next few months.

The US has been asking its allies to take part in a naval mission to protect shipping in the strategic Strait of Hormuz, at the mouth of the Persian Gulf, although European nations have been reluctant.

Britain has so far been the only nation to express willingness to join a maritime security mission. It has also been giving British-flagged vessels a naval escort since the Iranian Revolutionary Guard’s seizure of the Stena Impero.