Germany has suspended two soldiers in connection with macabre photos showing German troops posing with human skulls in Afghanistan.
RTL said its pictures were taken a year after the first batch
Four other soldiers - no longer in the army - are also being investigated over the images, which have shocked Germany.
The pictures were published on Wednesday in the popular daily Bild.
Since then photos of similar, separate incidents have emerged. RTL TV showed images of a soldier kissing a skull, and of skulls mounted in a pile.
The six soldiers identified are being investigated in connection with the Bild photos.
Defence Minister Franz Josef Jung said on Friday the two soldiers still serving "will no longer be a part of the German army".
Prosecutors have said the six could face charges of disturbing the peace of the dead, which carries a prison sentence of up to three years.
There is concern that the photographs could spark a backlash not only against German troops serving in Afghanistan, but against the entire Nato-led mission there, says the BBC's Steve Rosenberg in Berlin.
Germany has warned its embassies in Afghanistan and the Middle East to tighten security measures in case there is a violent reaction to the scandal, Reuters reported.
"Such grave misconduct is bound to endanger the safety of the soldiers serving in Afghanistan. These pictures will of course be published in the Islamic world and will be used against us by the Taleban and al-Qaeda," a spokesman for the main army union, Bernard Gertz, said.
So far, however, there has been little reaction from the Muslim world.
Germany has extended its mission in Afghanistan
The first pictures to emerge dated from 2003, the Bild newspaper said.
They included an image of a soldier holding a skull next to his exposed genitals, and of soldiers placing it on the bonnet of their jeep.
RTL said the second batch was taken in 2004.
The chief of staff of the German army, Wolfgang Schneiderhan, denied that a second, separate incident suggested such behaviour was common.
"It is another isolated case," he said. "It is individuals who have been led astray and haven't understood what they are doing."
'Germany's Abu Ghraib'
The images might not be as shocking as the infamous Abu Ghraib photographs showing US troops abusing Iraqi prisoners, but they have sparked widespread revulsion, our correspondent says.
Some newspapers are already calling the scandal Germany's Abu Ghraib, he adds.
Senior figures have called for a review of training given to the armed forces.
The Roman Catholic bishop assigned to the German military, Walter Mixa, said the scandal was "a warning signal" and that training for foreign deployments "must be improved".
The scandal coincided with a German announcement that its deployment in Afghanistan would be extended, and with a review of military doctrine that said Germany should take part in more overseas missions.