Spain will claim a colonial-era treasure that an American treasure-hunting firm says it found in a shipwreck if it turns out to be Spanish or was removed from Spanish waters, the culture minister said Monday.

"We will exercise all of our jurisdiction and rights in the hypothetical event that the find is part of Spain's heritage," minister Carmen Calvo said in Seville.

But Odyssey Marine Exploration said Monday the ship that yielded an estimated $500 million worth of gold and silver coins was not in Spanish territorial waters and was not the HMS Sussex, a shipwreck that Odyssey recently got permission from the Spanish government to search for in the Strait of Gibraltar.

Odyssey announced Friday that it had discovered a shipwreck it has codenamed "Black Swan" and 500,000 gold and silver coins somewhere in the Atlantic Ocean.

The Florida-based company would not say exactly where the ship was or name it, citing security concerns, but said the site was outside any country's territorial waters.

In March of this year Spain granted the company permission to search its waters off the Strait of Gibraltar for the HMS Sussex, which sank in a 1694 storm off the Rock while leading a British fleet into the Mediterranean Sea for war against France. The strait is the strategic waterway that connects the Atlantic and the Mediterranean.

But that permit was only for exploration, not for removing anything from the Sussex if it were found.

Odyssey denied that the wreck it found was the Sussex.

"We can confirm that the 'Black Swan' is not HMS Sussex, and that the 'Black Swan' was not found in waters anywhere near the shipwreck believed to be HMS Sussex," the company said in a statement released Monday. "Beyond that, we cannot confirm the identity of the shipwreck because we are not certain ourselves."

Speculation about the origin of the treasure has also focused on a wreck site near the English Channel that Odyssey recently petitioned a U.S. federal court for permission to salvage.

In seeking exclusive rights to that site, an Odyssey attorney told a federal judge last fall that the company likely had found the remains of a 17th-century merchant vessel that sank with valuable cargo aboard, about 65 kilometers, or 40 miles, off the southwestern tip of England. A judge granted those rights last Wednesday, just two days before Odyssey announced the discovery.

Odyssey has refused to say if the loot was from that site.

A spokeswoman for the Spanish Culture Ministry, Susana Tello, said a worrisome scenario would be if the shipwreck Odyssey discovered turned out to be Spanish — she said there are an estimated 400 shipwrecks in the Strait of Gibraltar — in which case Spain would claim the booty.

"At the very least the origin of the treasure is dubious," Tello told The Associated Press.

The ministry, which has say over cases involving Spain's cultural heritage, has ordered the Civil Guard to investigate the Odyssey case and tighten surveillance in Spanish waters to keep anything from being removed illegally.

Tello said news reports in Gibraltar say a chartered Boeing aircraft landed and took off from there Thursday, a day before Odyssey announced its find. She argued that that raises suspicions the treasure could have come from waters in or near the strait.