A scuba diver underwater is seen in the background of this undated image of the rusted wreck of the USS Spiegel Grove in Key Largo, Florida
A scuba diver explores the shipwreck USS Spiegel Grove. Key Largo, Florida, USA.
  • The Department of Transport warned people off exploring US shipwrecks in a notice Monday. 
  • All US shipwrecks are under MARAD's authority, it said, no matter where or when they sunk. 
  • Looting of old wrecks, as well as dangerous adventure tourism, has caused public alarm in recent weeks.

The Department of Transport has warned off would-be adventurers and salvage operators from exploring shipwrecks that fall under the authority of the United States.