A Vietnamese tanker linked to a Russian sanctions-busting investigation has been released after a week’s detention at a northern Spanish port, shipping data shows.

The 108,900-dwt Elephant (built 2007) was detained on 14 February at Ferrol.

It was held for technical and documentation problems, partly related to ship-to-ship transfers, according to Reuters.

Elephant has been removed from a list of current detentions compiled by the Paris MoU on Port State Control and Kpler tracking data showed the Elephant left Ferrol late Tuesday for the stated destination of Tallinn, Estonia.

Elephant’s detention came just days it transferred its cargo of vacuum gasoil to a Maersk Product Tanker vessel, the Maersk Magellan.

The 51,600-dwt Maersk Magellan (built 2010) was subsequently barred from unloading at Tarragona, Spain because of an apparent attempt to circumvent Russian sanctions, according to Spain’s transport ministry.

The ministry identified the problem from an earlier ship-to-ship transfer between Elephant and another tanker, the 46,100-dwt Nobel, in the Alboran Sea off the coast of Spain, which sailed under the Russian flag until 1 July.

Trying to land a cargo in the EU that had once been on board a tanker that flew the Russian flag after the invasion of Ukraine breached sanctions, it said.

Maersk Tankers, the pool operator which includes the Maersk Magellan, said the cargo would be taken outside of Europe. The tanker is currently stopped off the coast of Northern Cyprus while the charterer decides on a new destination.

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: Elephant and two MR tankers, all built between 2007 and 2009.

Spanish authorities have warned suppliers of ship-to-ship services that they risk breaching sanctions in a sign of growing disquiet over Russian oil transfers a few miles off the European coastline.

The port authority of the Spanish exclave of Ceuta contacted two businesses operating in the city earlier this month to warn them that they risked breaching sanctions for supplying equipment for STS transfers, according to local newspaper El Faro.

The Sea of Alboran has emerged as an increasingly popular spot for ship-to-ship transfers for aframaxes from Russian ports with larger tankers bound for Asia.