The United States on Friday threatened sanctions against "anyone providing support to the Adrian Darya 1," the Iranian oil tanker that has raised tensions between Tehran and the West.

Previously known as Grace 1, the ship has been bouncing around the Mediterranean after being held for six weeks by Gibraltar on suspicion that its cargo was bound for Syria.

The US Treasury Department declared that the vessel is now "blocked property" under an executive order that targets terrorists and those providing support to terrorism.

Read more: How Trump's sanctions are crippling Iran's economy

The order also levied sanctions against the ship's captain, Akhilesh Kumar, a 43-year-old Indian national.

"Anyone providing support to the Adrian Darya 1 risks being sanctioned," warned Sigal Mandelker, US under secretary for terrorism and financial intelligence. 

She said vessels like the Adrian Darya 1 allow Iran to "transfer large volumes of oil, which they attempt to mask and sell illicitly to fund the regime's malign activities."

After the vessel was impounded on July 4, Washington pressured Gibraltar, a British territory on the southern tip of Spain, to keep the tanker and its cargo of 2.1 million barrels of oil impounded.

Revenue source for Revolutionary Guards

The US insists the Adrian Darya 1's true owner is Iran's Revolutionary Guard, a paramilitary organization answerable only to Supreme Leader Ayatollah Ali Khamenei.

But the vessel was released on August 15 after Tehran promised its cargo — worth around $140 million (€127 million) — was not in violation of European Union sanctions on Syria.

Iran said Monday it had "sold the oil" aboard the tanker but refused to identify the buyer for fear of subjecting them to US sanctions. It said the owner will decide where to send the ship.

Oil sector experts believe Iran is still planning a ship-to-ship transfer of the oil, with Syria being a likely final destination.

Since the tanker's release, there has been much speculation as to its next port of call. Both Lebanon and Turkey have denied claims that the ship would sail to one of their ports.

Destination unknown

According to maritime traffic monitoring websites, the huge tanker is currently just west of the Mediterranean island nation of Cyprus.

Read more: JCPOA reeling, Iran's youth seek sustainable economic path

The US and Iran have been at loggerheads since Washington last year withdrew from the landmark 2015 nuclear accord, which sought to rein in Tehran's atomic ambitions.

The US reimposed and escalated sanctions on Iran, largely blocking the Islamic Republic from selling crude oil abroad.

The seizure of Grace 1 prompted Iran to impound a British-flagged tanker in the strategic waters of the Persian Gulf.

Washington has also blamed Tehran for a series of recent sabotage incidents targeting oil tankers in the Gulf region.

mm/ng (AFP, AP)

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