"Every illicit voyage helps sustain Russia's war machine. We are matching our sanctions with actions at sea," the EU's top diplomat Kaja Kallas tweeted.

EU foreign policy chief Kaja Kallas said the move was aimed at increasing pressure on what she described as "Russia’s shadow fleet"

A European naval mission boarded a Russia-linked oil tanker suspected of sailing under a false flag this week, the EU’s top diplomat Kaja Kallas said Wednesday.