An autonomous vehicle was used in 2015 to locate a Spanish galleon that sunk 300 years ago off the coast of Colombia with $17 billion in treasure, the research team that helped in the discovery said on Monday.

The San Jose, which was considered the “holy grail of shipwrecks,” was located with the help of an underwater autonomous vehicle operated by the Woods Hole Oceanographic Institution. The institution said it was holding the discovery under wraps out of respect for the Colombian government.

The treasure—which includes of gold, silver and emeralds-- has been the subject of legal battles between several nations as well as private companies.

Several weeks ago, UNESCO, the United Nations cultural agency, called on Colombia not to commercially exploit the wreck, whose exact location remains a state secret. The country hopes to build a museum and preserve the wreck, the Massachusetts-based WHOI said on its website.

The 62-gun, three-masted galleon, went down on June 8, 1708, with 600 people on board during a battle with British ships in the War of Spanish Succession.

WHOI was invited to join the search because of its recognized expertise in deep water exploration. The institute's autonomous underwater vehicle, REMUS 6000, helped find the wreckage of Air France 447 in 2011, which crashed in 2009 several hundred miles off the coast of Brazil.

It was REMUS 6000 that in Nov. 27, 2015, took some side sonar images that found the San Jose in more than 2,000 feet of water. The vehicle descended to 30 feet above the wreck to take several photographs, including some of the distinctive dolphin engravings on the San Jose's cannons, a key piece of visual evidence.

"The wreck was partially sediment-covered, but with the camera images from the lower altitude missions, we were able to see new details in the wreckage and the resolution was good enough to make out the decorative carving on the cannons," said WHOI engineer and expedition leader Mike Purcell.

The Associated Press contributed to this report