Russian President Vladimir Putin threatened Wednesday to seize European commercial ships if EU states carry out plans to confiscate and sell cargo taken from Russian-linked vessels, calling the measures piracy and robbery.

Putin delivered the warning aboard the missile cruiser Varyag during Pacific Fleet exercises off Sakhalin, in Russia's Far East. He said authorities in certain countries were trying to restrict the movement of vessels operated by Russian businesses in violation of international maritime law, The Moscow Times reported.

If the seizures proceed, Putin said, Moscow would be forced to respond in kind. He added that any Russian retaliation would not necessarily take place in the same waters, but wherever Russia considers it necessary and appropriate, including within the Pacific Fleet's area of responsibility, Meduza reported.

The warning follows the European Union's adoption in July of a mechanism allowing member states to sell oil, petroleum products and grain seized from tankers linked to Russia's so-called shadow fleet, the network of aging vessels Moscow uses to move crude in defiance of Western sanctions. The measure was part of the bloc's 21st sanctions package.

European countries and Britain have detained five tankers carrying Russian oil since the start of the year. The MV South Star was stopped July 20 in an operation involving EU states. France intercepted the tankers Grinch, Deyna and Tagor before releasing them, while Britain has held the Smyrtos, carrying 100,000 metric tons of oil, since June 14.

Sweden detained the dry cargo ship Caffa in March, which Kyiv said had been carrying grain from Russian-occupied Ukrainian territory. The Swedish Supreme Court ruled this month that the vessel should be handed to Ukraine, according to court documents cited by The Moscow Times.

Russia's Foreign Ministry separately accused the EU of using Operation Irini, the bloc's Mediterranean naval mission, to intimidate commercial shipping and obstruct freedom of navigation. An Italian-led inspection of a shadow fleet tanker in early August was the second such operation in under two weeks, Al Jazeera reported.

Putin had already described the seizures as piracy in late July, when he urged fleet commanders to act decisively within maritime law.