The information comes to light in an internal email from July within the Danish state-owned pilot company Danpilot, which the investigative media company Danwatch has taken part of.
The email states that reports from pilots have arrived that several ships have extra crew members who are likely Russians and wear military uniforms. The members are said to be "very active" and have photographed, among other things, bridge passages.
According to analyzes from Lloyd's List Intelligence, the shadow fleet consists of over 700 tankers, of which 444 are subject to punitive measures from the EU. Despite the sanctions, the ships pass through Denmark almost daily, as it is the only way out of the Baltic Sea after visiting the oil ports around St. Petersburg. Old tankers are used to circumvent the sanctions against the Russian oil export.
Danish authorities tell Danwatch that they are coordinating measures against the shadow fleet - and that they are collaborating with other affected countries.
Yet, no ship from the shadow fleet has been stopped by Denmark.