Britain summoned the Iranian ambassador on Tuesday to condemn what it said was a clear breach of the assurances it was given over the oil cargo of the tanker Adrian Darya 1, which had previously been detained for breaching EU sanctions.

"Iran has shown complete disregard for its own assurances over Adrian Darya 1," foreign minister Dominic Raab said in a statement, accusing Iran of reneging on a promise not to transfer oil from the tanker to Syria.

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Iran says oil tanker Adrian Darya 1 unloads cargo on Mediterranean coast

Britain said it would raise the issue at the United Nations later this month.

The vessel, formerly named Grace 1, was seized by British Royal Marine commandos on July 4 on suspicion of being en route to Syria.

Gibraltar released it on August 15 after receiving formal written assurances from Tehran that the ship would not discharge its 2.1 million barrels of oil in Syria.

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