Germany's defense ministry says it is investigating photos published by a popular newspaper that appear to show German troops in Afghanistan posing with a skull.

The daily Bild newspaper says the pictures were taken near Afghanistan's capital, Kabul, in 2003. The paper says it does not know where the soldiers obtained the skull or how old it was.

German Defense Minister Josef Jung called the pictures disgusting and incomprehensible. He said such behavior by German soldiers will not be tolerated.

Germany has about 2,800 troops in Afghanistan as part of the NATO peacekeeping mission. Germany's parliament voted last month to extend their deployment for another year.

The photos show the soldiers holding the skull up and fastening it to a vehicle like a hood ornament. Another soldier is shown exposing himself next to the skull.

The newspaper did not say how it obtained the photos.

Some information for this report was provided by AFP, AP and Reuters.