A Vietnamese-owned tanker has been detained in Spain, days after the launch of a Russian sanctions probe following its ship-to-ship (STS) transfer with a Maersk Product Tankers vessel.

The 108,900-dwt Elephant (built 2007) was detained at the northern port of Ferrol on Tuesday, according to the database of the Paris MoU on Port State Control.

The reasons for the detention were not clear but it followed an investigation by the Spanish authorities into the STS transfer of vacuum gasoil involving the Elephant and the 50,000-dwt Maersk Magellan (built 2010) on 6 February.

The inquiry revealed that the cargo originated from a tanker: the Seychelles-owned 46,200-dwt Nobel (built 1997) that had carried the Russian flag until 1 July.

Popular STS area

Spain’s transport ministry concluded that the trade breached the European Union sanctions regime and refused to allow the Maersk Magellan to unload its cargo at the port of Tarragona three days later.

The STS took place in the Alboran Sea near the Mediterranean gateway to the Atlantic.

The area has become popular for STS transfers of Russian oil from aframax tankers to larger vessels for onward voyages to Asia.

The activity has been a source of irritation for the EU, which has imposed sanctions on Russian oil exports but has limited ability to target STS transfers outside of the territorial waters of its member states.

The Elephant headed north around the coast of Spain after the STS and arrived at Ferrol on Saturday, according to Kpler tracking data. It was listed as having been detained three days later by the Paris MoU.

The Elephant is owned by Hung Phat Maritime Trading, based in Ho Chi Minh City, Vietnam, according to the VesselsValue database.

Hung Phat is listed as owning three ships: the Elephant and two MR tankers, all built between 2007 and 2009.

The port inspection regime of the 27-nation regime is focused on environmental, safety and working conditions but additional inspections can be ordered because of “cargo problems”, according to an MoU note.

The secretariat and the port of Ferrol have been approached for comment.

Maersk Tankers, which commercially manages the vessel on behalf of Maersk Product Tankers, said it carried out checks on both the Elephant and Nobel before deciding to go ahead with the trade.

“Maersk Tankers is currently in dialogue with relevant parties and the vessel is meanwhile awaiting further detailed instructions from charterers in relation to the discharge of its cargo,” the company said on Tuesday.