Copenhagen  - The Danish military Tuesday said it had launched an investigation against a soldier who published a book detailing his tour of duty in southern Afghanistan.

Thomas Rathsack is being investigated for possibly violating rules on confidential information and disclosing classified military information, Peter Otken of the Advocate General's Corps told local media.

The military last week went to court to get an injunction against Rathsack's book, arguing that it contained details of military operations which could hurt military security, and even potentially threaten national security.

A court on Monday ruled that it was too late to stop the book, citing that it had already been distributed as a special supplement by the daily Politiken and was also on the internet.

Formal charges have not been presented and Rathsack has not been interviewed yet, Otken said.

Rathsack served with one of the Danish military's elite units, the army rangers, and described his tours of duty in Afghanistan, Iraq and the Balkans in the book titled Ranger
- At War With the Elite.

The military and government officials have declined to offer details of what posed a threat but the military have also filed a separate police complaint against Politiken. (dpa)