Tanker broker Poten & Partners has raised safety concerns over the likelihood that Russia will increasingly rely on the dark fleet to move its oil.

Erik Broekhuizen, head of tanker research for the New York broking house, said most of the tankers involved in carrying sanctioned oil are older vessels that can rake rates that are two to three times higher than in above-board trades.

With reputable shipowners staying away, owners of dark fleet ships have purchased them specifically for the purpose of operating them in illicit trades with a view toward making their money back quickly, he wrote.