TALLINN — Russia has released a Greek-owned oil tanker which was seized on Sunday in Russian waters after leaving a port in Estonia, the Estonian public broadcaster ERR reported.

The Liberian-flagged Green Admire is now sailing in the Baltic Sea and is headed for the Dutch port of Rotterdam, according to ERR and the LSEG ship tracking data service.

The tanker was seized by Russian authorities after departing from the Estonian port of Sillamäe and using a designated navigation channel that crosses Russian waters, Estonia's foreign ministry said on Sunday.

Estonia's Foreign Minister Margus Tsahkna said that Russia's action against the Green Admire was likely a response to the Estonian navy's campaign against Russia's so-called "shadow fleet", in which it is inspecting tankers used to transport millions of barrels of Russian oil through the Baltic Sea.

"(The) incident shows that Russia continues to behave unpredictably," Tsahkna said on Sunday, referring to Moscow's detention of the Green Admire. "I have also informed our allies of the event," he said, referring to other NATO members.

To prevent similar incidents in the future, Estonia will redirect marine traffic to and from Sillamäe exclusively through Estonian territorial waters, the foreign ministry said.

A Russian fighter jet entered NATO airspace last week after Estonia’s navy had intercepted a suspected shadow fleet ship in its waters, according to Tsahkna.

Russia's shadow fleet is made up of aging tankers bought used, often by non-transparent entities with addresses in non-sanctioning countries such as the United Arab Emirates or the Marshall Islands, and flagged in places like Gabon or the Cook Islands.

The European Union has been targeting the ships, which sometimes also carry stolen Ukrainian grain, with sanctions. In February, 70 vessels believed to be part of the shadow fleet were added to more than 50 already listed.

EU foreign ministers are expected to slap sanctions on dozens more imminently. — Euronews