Iran is to free seven crew members from the detained British-flagged oil tanker Stena Impero, according to Iranian state TV.
Abbas Mousavi, a spokesman for Iran's foreign ministry, told the broadcaster they were being freed on humanitarian grounds and would be allowed to leave the country soon.
The Stena Impero was detained by Tehran on 19 July, two weeks after Britain detained an Iranian tanker – the Adrian Darya 1 – off the territory of Gibraltar.
The Iranian vessel, previously known as the Grace 1, was released in August amid speculation that it planned to transport its cargo to Syria, in breach of European Union sanctions.
It is carrying 2.1 million barrels of Iranian crude worth about $130m (£108.4m).
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Iranian officials have not revealed who bought the ship's cargo, only confirming that it has been sold.
The vessel switched off its Automatic Identification System (AIS) – its tracking beacon – on Monday afternoon, according to the ship-tracking website MarineTraffic.com.
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At its last report, the vessel, which is being pursued by the US, was 45 nautical miles (83km) off the coast of Lebanon and Syria, heading north.
US Secretary of State Mike Pompeo said intelligence suggests the vessel is heading to the Syrian port of Tartus – a short distance from its last-known position.
The US alleged in federal court that the ship is owned by Iran's Revolutionary Guard, a paramilitary organisation answerable only to Supreme Leader Ayatollah Ali Khamenei.
America recently described the Revolutionary Guard as a terrorist organisation, giving it greater power to pursue seizing its assets.

Meanwhile, Iranian President Hassan Rouhani warned Tehran would further cut its commitments under the 2015 nuclear deal.
"The third step [in reducing Iran's commitments] will be the most important one aRead More – Source