Euronav is investigating claims that one of its tankers was preparing to receive a cargo of sanctioned Iranian crude in a ship-to-ship transfer off the coast of Malaysia.

Campaign group United Against Nuclear Iran (UANI) told Euronav on Tuesday that its 441,600-dwt Oceania (built 2003) was alongside a Vietnam-flag vessel in the Malacca Strait that appeared to have loaded Iranian crude while its AIS was switched off in February.

The New York-listed Belgian tanker owner said it is investigating the allegation but said its due diligence checks suggested that the 105,200-dwt Abyss (built 1998) was carrying Iraqi crude.

The company said it is working with the US Office of Foreign Assets Control and counterparties to probe the allegations. It declined to say whether any oil was discharged into the Oceania but said an analysis of samples would form part of its inquiry.

The Oceania is a floating bunker supply vessel not involved in active trading and is used to store the company’s own oil. But space on the vessel is also rented out to other companies. The counterparty in this case was not identified by Euronav.

Kpler ship-tracking data showed the two vessels in close proximity on Thursday. Its analysts assessed that the cargo could have come from Iran.

Head of investor relations Brian Gallagher said Euronav is investigating the “serious” situation, to establish the source of the cargo.

“All of the work we have undertaken … has not given us any indication that this was anything other than oil of Iraqi origin,” he added.

“This allegation has been made and we’re now working very hard to find the evidence of where the cargo has actually come from.”

Earlier checks had given the cargo a “clean bill of health”, Gallagher said, so “we want to see where breaches have occurred, if they have occurred”.

Euronav CEO Hugo De Stoop. Photo: Euronav

Gallagher said if the crude is found to be of Iranian origin, Euronav would take “affirmative” action, but he declined to give details. The Associated Press reported that the oil would be returned to the third party that delivered it.

UANI said in a letter to Euronav that it believes the Abyss took on the crude at the Iranian port of Bandar Mahshahr, a specialist oil export hub, after turning off its AIS tracker on 18 February.

The group said it had found a satellite image that it believed showed the Abyss at the port on 21 February. The Abyss is operated and beneficially owned by Petrovietnam, according to VesselsValue.

Vietnamese-owned vessels have previously been linked to trades involving sanctioned oil.

The Vietnamese-owned 108,900-dwt Elephant (built 2007) was detained by Spanish authorities for a week earlier this year after a sanctions probe linked to a trade involving 720,000 barrels of Urals crude loaded at the Baltic port of Ust-Luga.

“Any other signs of manipulating AIS transponders should be considered red flags for potentially illicit activity,” said Mark Wallace, a former US ambassador to the United Nations, according to a tweet by UANI.

The US reimposed sanctions on Iran in 2018 after former president Donald Trump withdrew from a deal that would have allowed Tehran to trade its oil in return for restrictions on its nuclear programme.

The US warned in January that it would crack down on booming Iranian oil exports after data suggested they had reached their highest level since the US dumped the deal.

Vortexa said Iran exported 1.4m barrels per day in December, with most of it going to China.

The data analyst identified 181 tankers carrying Iranian crude in 2022. Half of them were more than 20 years old.