The complaint was filed in the German city of Karlsruhe on behalf of 11 former Iraqi detainees at Abu Ghraib prison and a Saudi held at a US "war on terror" detention center in Guantanamo Bay, Cuba.
"From what I know, from the press accounts, it certainly sounds frivolous to me," Pentagon spokesman Bryan Whitman told reporters.
Whitman, who said the Pentagon had not yet seen the suit and knew of it only through press accounts, said the United States already has thoroughly investigated abuses at Iraq's Abu Ghraib prison.
German law allows the pursuit of warcrimes cases regardless of where they originate in the world. A similar attempt to prosecute Rumsfeld in Germany was rejected two years ago.

Copyright AFP (Agence France-Presse), 2006