Russia's SHOT news outlet reported last week on its Telegram that two Russians, a Lithuanian and two Ukrainians have been locked up on board a Cameroon-flagged fishing boat Volopas for eight months.

"They found themselves hostage to a financial and property dispute between the ship-owning company and a local agent company," Russia's foreign ministry told RIA.

Diplomatic efforts to repatriate the sailors have not been successful so far, the foreign ministry said.

(Reporting by Lidia Kelly in Melbourne; Editing by Jamie Freed)