Algeciras, Spain (AHN) - Spanish authorities on Tuesday said they seized a U.S.-registered treasure-hunting ship for allegedly taking an estimated $500 million in gold and silver from a sunken Spanish galleon.

The Spanish Navy corvette on Tuesday intercepted blocked the Odyssey Explorer after it left the British territory of Gibraltar and threatened to open fire when the captain refused to let police on board.

The treasure-hunting vessel belonging to U.S. company Odyssey Marine Exploration, was escorted to the Spanish port of Algeciras where police could complete a search. The boat's American captain, Sterling Vorus, was also arrested.

"They threatened that we must obey or they would use deadly force," Ali Nessar, a company representative on the boat said. "We were forced at gunpoint to come to Algeciras."

The Odyssey Explorer incident is the latest in a dispute beginning in May when Madrid said the American ship's discovery of the treasure might have come from Spanish waters or from a Spanish galleon in international waters.

In both cases Spain remains the rightful owner, the government claims.

However, the Florida-based Odyssey Marine Exploration disputed the Spanish claims saying it has legally discovered 17 tons of silver coins plus gold while working on a wreck code-named "Black Swan" at a secret location in the Atlantic Ocean adding the discovery was made outside of any country's territorial waters.