Florida deep-sea explorers who raised an estimated $500 million treasure from the 200-year-old wreck of a Spanish galleon should give all the loot back to Spain, a federal magistrate judge said.

But the two-year tug-of-war over the 17 tons of silver coins and other artifacts from what is believed to be the Nuestra Senora de las Mercedes y las Animas is likely far from over.

Odyssey Marine Exploration said it will oppose Wednesday's written recommendation by U.S. Magistrate Judge Mark Pizzo, which will be considered by another federal judge who will issue an order later.