Spanish Civil Guards on Thursday heightened a battle over a $500 million treasure of gold and silver coins from a shipwreck when they seized a vessel belonging to a Tampa, Fla.,-based company.

The Ocean Alert was seized around 9 a.m., three miles off the southeastern coast and taken to the nearby port of Algeciras to be searched, the Civil Guard said.

The Civil Guard acted on an order of a Spanish judge who in June instructed police to seize two vessels of Odyssey Marine Exploration if they left the British colony of Gibraltar — on Spain's southern tip — and entered Spanish waters.

Odyssey, a treasure hunting company, said it had found the Colonial-era shipwreck on May 18, and the coins have been flown to the United States from Gibraltar.

Spain filed claims last month in a U.S. federal court over Odyssey's find, arguing that if the shipwrecked vessel was Spanish or was removed from its waters, the treasure belongs to Spain.

Odyssey insists the shipwreck was outside any country's territorial waters, but has not given its exact location or the ship's name.

According to a release from the company, Odyssey has provided a 109-page affidavit to authorities in the Spanish Federal government, the Junta de Andalucia, the United Kingdom, Gibraltar and the United States detailing Odyssey's activities concerning the discovery.

"We always attempt to work with appropriate governments on shipwreck projects in which they may have an interest and look forward to addressing any issues of claims or legal jurisdiction related to the (shipwreck site) in the proper venue, which is U.S. Federal Court," Odyssey co-founder Greg Stemm said in a news release.

In Britain, the find generated press reports that Odyssey had salvaged the wreck of the long-sought British vessel Merchant Royal, which sank in bad weather off England in 1641. Odyssey has not confirmed or denied these reports.