Sotheby's officials said Wednesday they had withdrawn 11 Soviet military decorations from the auction on Russia's request.
"We still hope that our decorations will turn out to be among those exhibited at the auction," the museum director, Alexander Nikonov, said.
Under Russian law, Soviet military medals cannot be traded. Only the holder of a decoration can take it outside the country without authorization from the cultural watchdog.
Media reports said Wednesday Interpol had joined an investigation into how the awards had been shipped to Britain.