Panama is canceling the registration of six ships sailing under its flag that were sanctioned by the UK last week, a boost for Western nations that have slapped sanctions on Moscow’s oil exports.

The Panama Maritime Authority said it will carry out “expedited cancellation” of the vessels after the UK blacklisted 30 ships last week.

Merchant ships sail under the flags of various countries that aren’t necessarily closely linked to the ship’s ownership, with so-called flag states typically playing a key role in ensuring industry safety standards. Panama is the second-biggest flag state in the world, just behind the Liberian registry.

The de-listing follows a pledge by Panama’s maritime authority in October to penalize vessels sanctioned by the US, European Union, UK and United Nations. Gaining support from one of the largest shipping administration bodies in the world was a coup for the Group of Seven and its allies, which have sought to impose a price cap of $60 a barrel on Russian exports.

Despite measures taken against a number of ships by the UK, US and EU, Moscow continues to export large volumes of crude. There can also be knock-on effects of switching flags, with vessels instead moving to ones that are less well regulated from a safety standpoint.

“Safeguarding the prestige of our flag is a top priority for this administration,” Ramon Franco, director general of merchant marine at the Panama Maritime Authority, said in a statement. “The state has a fundamental responsibility to protect the integrity of the Panamanian ship registry, ensuring it remains free from international sanctions and unlinked to vessels associated with such listings.”