The Russian Navy has joined the hunt for the hijacked Maltese registered cargo ship as information emerged it could have headed into the Atlantic Ocean because it did not approach the Straits of Gibraltar.

"Under the orders of President Dmitry Medvedev all Russian navy ships in the Atlantic have been sent to join the search for the Arctic Sea," news agency Itar Tass quoted Navy commander, Admiral Vladimir Vysotsky, as saying.

The Malta Maritime Authority issued an update on the Finnish-owned MV Arctic Sea yesterday, which "disappeared" late last month as it approached the English Channel.

The ship, with 15 Russian crew on board, had been attacked by a dozen pirates purporting to be anti-drugs police. They allegedly assaulted, tied, gagged and blindfolded the crew.

The ship, which was carrying sawn timber, made a mandatory radio call to British coastguards on July 28 as it prepared to enter the sea lanes in the Strait of Dover. The person on board told Dover Coastguard the ship was due to arrive in northern Algeria on August 4.

The vessel was last recorded on a ship tracking system off the coast of Brest, northern France, on July 30 and it was apparently later spotted by a Portuguese coastal patrol plane. It has since disappeared.

The authority said there has been no communication with the ship and it was continuing to work with various jurisdictions to establish the ship's location and well-being of the crew.

The activities are being overseen by a security committee which meets daily. It is composed of representatives of the police, the Armed Forces of Malta and the authority.