A wide-ranging cartel investigation is rocking Greece's two major ports, with authorities suspending six pilots, the harbour master of Thessaloniki and the chief pilot in Piraeus.

A total of 18 people were arrested as part of the probe, Greek police said in a statement, without identifying anyone by name. Several media reports and sources contacted by TradeWinds said that owners of four tug companies and the Thessaloniki harbour master are among them.