MOSCOW, August 11 (RIA Novosti) - The Finnish owner of a cargo ship, crewed by Russians, that went missing off Portugal's Atlantic coast on August 1 has asked Russia to assist in tracing the vessel, which may have been hijacked.

"The Solchart company and me personally are counting, above all, on Russia's assistance in the search for the missing vessel and its crew," Viktor Matveyev, the company's executive director, said.

The dry cargo vessel, the Arctic Sea, was due to arrive at the Algerian port of Bejaia on August 4.

According to crew members, on July 24, masked men claiming to be police stopped the Arctic Sea in the Baltic Sea and tied up the crew, after which they searched the vessel.

The crew is reported to have said the men then left the ship after the 12-hour ordeal and the Arctic Sea resumed its voyage.

The Times newspaper cited a Maritime and Coastguard Agency representative as saying "We thought we had spoken to a member of the crew but of course it could have been someone with a gun pointed at their head or a hijacker."

Mark Clark said that the ship had last been seen by a Portuguese patrol vessel.

"This is the last information we have on the ship. Where she is now no one knows," Clark said, adding "no one can recall a hijacked ship being taken through the [English] channel."

According to media reports, the Arctic Sea, which flies the Maltese flag, had a crew of 13 sailors on board as of late March.