An American sea explorer has found the remains of a World War II merchant ship along with a cargo of platinum bars worth an estimated $3 billion.

The precious metals are thought to have belonged to the USSR and the UK, who were going to use them to pay back the US for aid. If this is correct, it is the world's most valuable find of its kind.

“We were working off the coast back in 2007 when one of our researchers came across recently declassified documents from Moscow and the US Treasury department that led us into a new search,” Greg Brooks, a treasure hunter from Sub-Sea Research, told RT.

As it turned out, the USSR had shipped these goods to Great Britain and then to the US as payment for the lend-lease program.

The search was far from easy thanks to the weather and conditions.

“It’s an extremely hazardous area we were working in,” Brooks said. “The currents out there were anywhere from two knots to six knots. We’ve had some severe weather this past season. The equipment was going down over 700 feet trying to enter the wreck.”

Last but not least, it took the crew an immense effort to find the ship.

“The US Navy documents said the ship went down off Cape Cod and that was where we started to look,” Brook recalled. “But it wasn’t anywhere near. We had to cover 150 square miles before we actually found the wreck.”

At first they were worried that someone would come and take their treasure but, luckily for them, this did not happen.

“Right now, we are facing no competition,” Brooks told RT. “We have a US Admiralty claim on the vessel and no one has come forward up to this day. In early 2009 we filed legal notices in all the major newspapers, the Wall Street journal, the New York Times, the Globe etc, in accordance with maritime law.”