Germany's defense minister expressed horror Wednesday at photos that appeared to show German troops in Afghanistan posing with a human skull and pledged that any soldiers found to be involved would be punished.

The macabre pictures were printed by Germany's biggest-selling daily, Bild, which said they showed German peacekeepers near the capital, Kabul, in early 2003.

The uniformed men were seen holding up the skull and posing with it on a jeep; one is seen exposing himself with the skull. Bild's headline declared: "German soldiers desecrate a dead person."

The newspaper said it was unclear where the skull came from, or whether it belonged to an Afghan or dated back to the Soviet occupation in the 1980s. It did not say how it obtained the photos.

"It is completely clear and unambiguous that such behavior by German soldiers ... can in no way by tolerated," Defense Minister Franz Josef Jung told reporters. "These pictures arouse repugnance and horror."

Jung said that "we are conducting the investigation at full steam." If the incident is confirmed, he added, those involved will face "disciplinary or even criminal measures."

"Anyone who behaves this way has no place in the Bundeswehr," the German military, Jung said.

Military chief of staff Gen. Wolfgang Schneiderhan said two possible suspects had been identified and were being questioned. One of them is still with the Bundeswehr and the other has left the army, he said.

"The matter has been handed over to prosecutors," Schneiderhan said, without elaborating.

Germany is proud of its post-World War II military training rules, which reflect lessons drawn from the Nazi era by urging soldiers to take responsibility for their actions.

Jung said the incident shown in the photos is "diametrically opposed to the values and ways of behavior" that German troops are taught in training.

Germany currently has about 2,800 troops in NATO's International Security Assistance Force, or ISAF, in Afghanistan.

Wednesday's photos came a week after lawmakers decided to investigate unrelated allegations that German special forces in Afghanistan abused a prisoner who later spent years in the U.S. military's prison at Guantanamo Bay, Cuba.

Murat Kurnaz, a German-born Turkish citizen, has claimed that two German soldiers came to interrogate him at a camp near the southern Afghan city of Kandahar in 2002 and slammed his head into the ground.

The Defense Ministry has said that German soldiers questioned about the allegations recalled the presence of a German-speaker among prisoners they helped guard near Kandahar, but that the only contact they remembered was one soldier calling out to the man.