FOLLOWING a circuitous route around Cyprus and multiple U-turns over the weekend, the  Iranian oil tanker Adrian Darya 1, formerly Grace 1, had slowed to a 1.3 knots less than 50 nautical miles off the coast of Tartus Sunday night amid strong indications that its cargo of 2m barrels of Iranian crude will finally be discharged in Syria.

If that happens it will be a violation of the terms of its release by Gibraltar authorities earlier this month and the delivery will inevitably reignite diplomatic tension between European, US and Tehran. 

The US Treasury Department  late Friday just as US Secretary of State Mike Pompeo claimed that the tanker at the centre of a confrontation between Washington and Tehran was indeed destined for Syria, despite the assurances offered to the UK.

Iran had previously given written and verbal assurances to the UK that the tanker and its cargo of 2.1m barrels of crude would not sail for a Syrian refinery in exchange for the order being lifted.

However, Mr Pompeo said in a tweet late on Friday: “We have reliable information that the tanker is underway and headed to Tartus, Syria.”

Until Saturday the vessel’s stated destination had remained Turkey’s Iskenderun port, 200 km (124 miles) north of Syria’s Baniyas refinery, however that was quickly changed amid a flurry of course re-directions to ‘FOR ORDER’.

The US intelligence pointing to Syria suggests that a ship-to-ship transfer of cargo may now be attempted.

In a separate statement issued late Friday The US Treasury Department formally blacklisted the Adrian Darya 1 and sanctioned its captain, reiterating warnings to the wider industry that any companies found to be assisting the ship would find themselves targeted by US sanctions.

“Vessels like the Adrian Darya 1 enable the (Islamic Revolutionary Guard Corps-Quds Force) to ship and transfer large volumes of oil, which they attempt to mask and sell illicitly to fund the regime’s malign activities and propagate terrorism,” Treasury Under Secretary Sigal Mandelker said in a statement.

“Anyone providing support to the Adrian Darya 1 risks being sanctioned,” she said.

The robust warnings suggest that US is prepared to target any ship-to-ship transfer operations as part of its hard-line stance against Tehran and continuing efforts to halt the progress of the Adrian Darya 1.

Mr Pompeo had earlier said that if the tanker went to Syria, Washington would take every action it could consistent with US sanctions. 

While the US seems convinced that the oil is headed for Syria, this is only the latest twist in an increasingly erratic series of moves by the now notorious tanker with its every move being tracked by governments and media internationally. 

Reports earlier on Friday had suggested that the vessel was in fact headed for Lebanon.

It was originally thought to be headed for Greece, but has changed course several times in the past week.

Media reports on Friday cited Turkey’s Foreign Minister Mevlut Cavusoglu as saying the vessel was heading for Lebanon.

Lebanon’s energy minister later said the country had not received a docking request from the ship.

“This tanker is not heading actually to Iskenderun [in Turkey], this tanker is heading to Lebanon,” Mr Cavusoglu was reported as saying during a visit to Oslo.

“We still buy gas from Iran, but we don’t buy oil,” he added.

Mr Cavusoglu said Turkey was monitoring the vessel’s progress “very closely”.

Lebanon’s Energy Minister Nada Boustani said on social media his country does not handle Iranian oil.

“The energy ministry does not buy crude oil from any country and Lebanon does not own a crude oil refinery,’’ he said. “There is also no request for the Adrian Darya 1 oil tanker to enter Lebanon.”

The ship was detained by British Royal Marines on suspicion of transporting crude oil to Syria, in violation of European Union sanctions against the country.

A court in Gibraltar ordered its release on August 15 despite a last-minute legal bid by the US to have it detained.