MIAMI, FL (EFE).- A Florida treasure-hunting firm must hand over to Spain the $500 million in gold and silver coins the company salvaged more than two years ago from the bottom of the Atlantic, U.S. District Judge Steven D. Merryday ruled.

The judge rejected the arguments offered by Odyssey Marine Exploration, Inc. to support its claim to the treasure.

While giving Odyssey 10 days to turn over the hoard, Merryday left the door open to extending that deadline to accommodate a possible appeal by the Tampa-based company.

Merryday found that the treasure recovered by Odyssey came from the Nuestra Señora de las Mercedes, a Spanish navy frigate destroyed in battle in 1804, and that the vessel and its contents rightfully belong to Spain.

He thus endorsed a June 3 report by federal Magistrate Mark Pizzo, who concluded the wreck was subject to the principle of sovereign immunity and that the valuables should be handed over to Madrid.

The Mercedes sank in action against a British fleet on Oct. 5, 1804, off the coast of southern Portugal, and Spain claims not only the vessel and cargo, but a right to preserve the gravesite of more than 250 Spanish sailors and citizens who went down with the frigate.

Odyssey, however, contends that Pizzo ignored "clear and convincing evidence of the commercial nature of the Mercedes' mission at the time of her demise," a factor the firm "believes legally nullifies the claim to sovereign immunity of that vessel."

"The majority of the coins aboard the Mercedes were merchant-owned, commercial cargo being shipped as freight for a fee and were never owned by Spain," Odyssey maintains. EFE