MOSCOW (AP) — News agencies say Russian naval ships are joining the search for a cargo ship with Russian sailors that has gone missing off Spain.

ITAR-Tass says ships from Russia's Black Sea fleet will begin searching for the Arctic Sea and its 15 Russian crew members.

Officials say contact was lost with the ship, which was carrying lumber from Finland to Algeria, on July 28.

Days earlier, masked men who identified themselves as police officers briefly seized the ship in Swedish waters and beat up the crew.

But Swedish authorities said they hadn't searched any ships.

Russian maritime expert Mikhail Voitenko said the ship's cargo belonged to Finnish wood products giant Stora Enso Oyj and could be worth up to $1.5 million.