TAMPA, Fla. – A ship belonging to Florida deep-sea explorers has left Spanish waters, ending the latest round in an increasingly nasty dispute with that nation’s government over the rights to a vast sunken treasure.

Odyssey Marine Exploration’s ship chugged out of Spanish waters Thursday, a day after Spanish authorities released the vessel. They seized the ship July 12 after it left British-controlled Gibraltar to search the vessel for clues as to the origins of an estimated $500 million in silver coins and other artifacts salvaged from a still undisclosed shipwreck.

The seizure of the 240-foot Ocean Alert culminated months of tense talks between Odyssey officials and the Spanish government, detailed in a 109-page affidavit the company prepared for Spain’s Culture Ministry. Odyssey provided a copy of the document to The Associated Press.

“It’s been very frustrating for everyone,” said Aladar Nesser, Odyssey’s director of international relations, who is trying to determine if the company’s other ship, Odyssey Explorer, will be allowed to leave British-controlled Gibraltar without interference from Spain.

At the heart of the dispute is Spain’s claim that it has a right to share in the treasure if it was recovered in territorial waters or is connected to the nation’s heritage in any way.

Citing security and other concerns, Odyssey will not disclose the location of the shipwreck, code-named “Black Swan.” The company says it’s not yet sure of the identity of the sunken ship, which yielded 17 tons of coins that were flown to the United States in May.

The secrecy has contributed to a growing mistrust of the Tampa-based company among some in the Spanish government, a sentiment that has been fanned by the country’s media.

“Spain has reason to believe Odyssey has recovered Spanish property without authorization,” said James A. Goold, an attorney who filed a claim in U.S. federal court on behalf of Spain.

Odyssey co-founder Greg Stemm said he resents the company’s growing reputation as modern-day pirates.

The company, he said, has “bent over backward” to communicate with the Spanish and other governments about its movements and treasure searches. And Odyssey has gone to U.S. federal court to seek exclusive rights to suspected wreck sites so anyone in the world with a potential claim would have a proper venue.

“That’s the great irony,” Stemm said. “How much more straightforward can you be than turning over the site to the U.S. federal court and following U.S. federal court orders? Does that really sound like piracy to you?”

In Odyssey’s affidavit, Stemm noted that Spanish authorities last year declined the company’s invitation to be part of pending search and salvage projects that could yield riches and have cultural significance to the nation.

But two weeks after Odyssey made headlines with news of the “Black Swan” treasure, Spain filed a claim in federal court in Tampa and has tried to force the company to disclose more details. That could happen as early as Monday, when Odyssey’s next court filing is due.

Culture Ministry spokeswoman Diana Lara said Thursday that Spain’s next legal move will depend on what Odyssey reveals in court.

Even if another country or party is able to prove a claim to the shipwreck and its cargo, Odyssey said it would apply for a salvage award in U.S. federal court, which has jurisdiction over admiralty cases. In similar cases, salvage companies are usually awarded a large percentage of the recovery.

Some experts believe Odyssey found the wreck of the Merchant Royal, a British ship loaded with tons of Spanish coins that sank off the southwestern tip of England in 1641. The company received exclusive salvage rights to a wreck site in the area where the Merchant Royal is believed to have gone down.

But Spanish officials say circumstantial evidence indicates otherwise. Odyssey acknowledges operating near Spanish waters this year, searching for another undisclosed wreck in international waters with the full knowledge of the government, according to the affidavit.

In March, before the “Black Swan” story broke, Spanish officials gave Odyssey permission to resume its search for the wreck of a British vessel, the HMS Sussex, in the western Mediterranean Sea.

Despite Odyssey’s emphatic statements to the contrary, some in Spain believe the “Black Swan” treasure came from the Sussex, which was leading a British fleet into the Mediterranean for a war against France in 1694 when it sank in a storm off Gibraltar.

Spanish media reported that Odyssey operated in the region in March, but Odyssey said it was there only to sink a prop treasure chest as a part of a contest promotion connected to Disney’s movie, “Pirates of Caribbean: At World’s End.”

Stemm said the company typically uses Gibraltar, a British territory on the southern tip of Spain, as a base for any of its operations in that part of the world.

A service of the Associated Press(AP)