The Ministry of Defence has launched an investigation after sensitive Nato military plans turned up on the Internet, an MoD spokesman said today.
The inquiry was ordered after a nine-page document detailing rules of engagement for Nato soldiers serving in Kosovo appeared on the computer screens of a London publishing company, according to The Sunday Telegraph.
An MoD spokesman said: "We have been made aware of a computer virus being found which contains text apparently relating to military matters and this has been determined to originate from outside the UK.
"Appropriate measures have been taken to investigate the matter."
Nato spokesman Jamie Shea told The Sunday Telegraph: "If it proves true that a Nato document has got into the public domain, it will be a matter of great concern to us.
"These are sensitive Nato documents. We would like to keep them classified and prevent them being comprised."
The document features the "Rules of Engagement for Land Operations", which cover the circumstances under which "appropriate measures, including the use of deadly force" may be used, the paper says.
It tells Nato troops they should hand over war criminals to the International Criminal Tribunal for the former Yugoslavia within 48 hours of capture.
According to the newspaper report, a military official ruled out the possibility that the document had been obtained by sophisticated hacking into military computers.
It had ended up in the public domain "by mistake" and the investigation would try to establish how that had happened, he said.Reuse content