Spain ? 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 about 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 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.