MADRID: Odyssey Marine Exploration, the U.S. treasure hunter, has acknowledged that it recovered more than 11,000 Spanish gold and silver coins as part of its much-publicized haul from a shipwreck whose ownership is being challenged by Spain, court papers show.

Britain has given Spain copies of two export licenses that Odyssey officials filed with the Gibraltar government detailing the booty it shipped out to the United States on two private transport planes. The treasure was flown to New York on April 10 and May 14.

The Spanish government filed the export licenses late Wednesday with U.S. District Court in Tampa, Florida, where Spain is challenging Odyssey’s petitions to exclusive salvage rights on three shipwreck sites that the company said it discovered this year in the Atlantic and Mediterranean.

Besides the 10,800 silver and 203 gold coins, Odyssey told the Gibraltar customs authorities that it also brought to the surface three gold boxes; copper, tin and bronze ingots; a cannonball; and a bronze pulley wheel.

It estimated the value of the trove at $1.49 million.

In its application for the second export license, Odyssey said it was transporting “557 plastic buckets containing clumps of encrusted silver coins” and four copper ingots now worth an estimated $2.5 million.

The Tampa company made international headlines when it announced in May that it had recovered more than 500,000 silver coins from a shipwreck it discovered in the Atlantic.

But until now, Odyssey has declined to say where it had found the ship to prevent ransacking by other treasure-hunters and speculation about the value of the coins.

Spain claims it has a right to any of its historical property under international law.

It has demanded that Odyssey release the details of its findings to determine whether it should continue to pursue ownership.

The legal battle came to a head this summer when the Spanish Civil Guard boarded Odyssey’s ship Ocean Alert as it left Gibraltar after a Spanish judge issued a search warrant.

James Goold, a lawyer who is representing Spain, said “that from the start of this action Odyssey has concealed information required by” the court and “continues to do so now.”

He asked a federal judge to dismiss Odyssey’s salvage-right claims on all three shipwrecks, arguing also that the district court did not have jurisdiction under the Foreign Sovereign Immunities Act to decide what rightfully belongs to Spain.

Odyssey said that the treasure was recovered from the bottom of the Atlantic Ocean about 180 nautical miles west of Gibraltar.

It had code-named the shipwreck the Black Swan, but some Spanish historians say they believe it may be the Nuestra Señora de las Mercedes, which was sunk by a British fleet off the coast of Portugal in 1804.

“Nothing recovered to date from the subject unidentified shipwreck vessel confirms an interest in the artifacts of any third party including the Kingdom of Spain,” Allen von Spiegelfeld, a lawyer for Odyssey, told a judge last month.

Spain is challenging ownership on the three shipwreck sites discovered by Odyssey this year, including a passenger ship that sunk off the coast of Sardinia in 1915 and a vessel it found about 40 nautical miles off the coast of Lands End, Britain.

Spain asked that the court, if it denies its motion, require Odyssey to fully disclose the information it has on all three shipwreck sites.

A judge has given both sides until next month to come up with deadlines for future filings.