Valletta, Malta - The hijacked ship Arctic Sea never disappeared and its movements had "always been known" to a maritime security committee, the Malta Maritime Authority said Tuesday afternoon.

The investigating authorities of Finland, Malta and Sweden chose not to disclose any sensitive information in order not to jeopardise the lives and safety of the persons on board and the integrity of the ship, the Maltese authority said in a statement.

The Russian navy arrested eight men accused of hijacking the Maltese-registered freighter near Sweden and forcing the crew to sail to West Africa in what turned out to be a puzzling maritime mystery. The nationalities of the detained persons have been confirmed to be Estonian, Latvian and Russian.

The Maltese authority said it would continue with a detailed investigation into the case and was in contact with the Russian authorities regarding the probe.

"Malta as the flag state administration is also endeavouring to ensure that the ship is granted a safe berth to allow for the required investigations into the seaworthiness of the ship," it said.

The freighter was transporting lumber worth some 1.3 million euros (1.8 million dollars) en route for Algeria. The fate of the Arctic Sea became a mystery when a group of armed men, allegedly posing as drugs enforcement officers, boarded the vessel in Swedish waters.(dpa)