Forensic analysis of a pen drive recovered from a Navy War Room leak case accused has revealed that he not only passed on India's secret defence plans to overseas agents but also counter-plans based on intelligence about war strategies of foreign powers.

A large chunk of highly confidential defence data on foreign navies, particularly Israel's, new-found nuclear ally USA and neighbour Pakistan, was allegedly leaked to fellow conspirators abroad by sacked IAF officer S L Surve, CBI sources said, adding that it compromised the country's counter-plans meant for the next 20 years.

Some of the files pertaining to the command and control operations of the US Navy have also been found in a jet flash pen drive recovered from another accused, Vijender Rana, who was posted at the Directorate of Naval Operations , the sources said.

Tests on the 128 MB Kingston-made Data Traveller model pen drive by the APFSL in Hyderabad has brought to light how the alleged spy ring used top defence personnel posted at the DNO, the 'operational hub of the Indian Navy', in South Block to access over 10,000 pages of confidential files on national security.

The DNO plans and processes cases and coordinates all operationally relevant exercises involving foreign navies and the Coast Guard, they added.

The files, all of which are marked 'highly confidential document relating to national security', have been listed in the annexures of the CBI chargesheet as having been found in the pen drive recovered by Air Force Intelligence from the house of Surve, who has since been sacked.

A total of 3,603 pages of sensitive information has been recovered from the pen drive and the majority of files, including the ones pertaining to foreign navies, were 'deleted files which were forensically recovered', the agency said.

The 'compromised' files on foreign navies are two folders headed 'Areas of Co-operation with Israel', an 11-page PDF document on the same topic, a one-page document dated February 16, last year titled 'Exercises with Foreign Navies' and an 88-page Internet file on the doctrine for command, control, communications and communication system support to Joint Operations authored by the Department of Navy, USA, the CBI said in its chargesheet.

A similar 67-page file dated October 1, 1996 relating to US Navy maneouvres has also been recovered from the same pen drive.

Closer home, the CBI has recovered a 'Top Secret' 19-page script for presentation on Pakistan war game prepared on May 17, 2005, agency sources said.

"The presentation was obtained by the intelligence channel on the prospective plans of an enemy country... this information would have determined the Indian Navy's counter-palnning, which has now been compromised," CBI said in the chargesheet. "Investigation so far has disclosed that Kulbhushan Parashar (a defence agent and an accused in the case) had exchanged pen drives at least on three occasions with Surve and at least twice with Rana."