NEW DELHI, INDIA: A memo that triggered a U.S. investigation into a possible cyber-attack by Indian military intelligence is probably a fake, but it is clear from leaked documents that serious security breaches did take place.

A little-known hacker group, 'Lords of Dharmaraja', began posting the documents last year, but only drew widespread attention after the anti-virus software firm Symantec confirmed on Saturday that a segment of its source code had been accessed by the group.

Reuters has obtained a large digital cache appearing to contain emails that were posted by the group but were quickly blocked by file-sharing sites.

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Dated between April and October last year, many of the emails were addressed to Bill Reinsch, a member of an official U.S. commission monitoring economic and security ties between the United States and China, including cyber-security issues.

Military and cyber-security experts in India say the hackers may have created the purported military intelligence memo simply to draw attention to their work, or to taint relations between close allies India and the United States.

"There is some malicious intent, but to try and work out who has done it, given the current nature of the Internet, is an exercise in futility," said Cherian Samuel, a specialist on cyber-security and Indo-U.S. relations at India's Defense Ministry-funded Institute for Defense Studies and Analyses.

Speculation has focused on India's neighbors, arch-rival Pakistan and China, both of which are active in cyber-operations.

"It's also possible that Pakistan's hackers have done it, or China's hackers," said Mukesh Saini, an expert on cyber-security who served on the secretariat of India's national security council, an intelligence agency, until 2006.

But if that were the case, he said, the attackers could be acting without state sponsorship.

"Pro-Indian and pro-Pakistan individuals and small hacker groups have been attacking each other's government and non-government websites, with or without the consent of their government, for a very long time," he said.

INCONSISTENCIES

Two Washington sources close to the U.S. China Commission said that while they were positive the commission was a target for Chinese intelligence, they found it hard to believe its activities were of any interest to Indian intelligence.

They said it was possible that Chinese operatives forged the document to embarrass both the commission and the Indians.

Other Washington officials, however, said it was equally possible, if not more plausible, that the alleged Indian intelligence document was genuine and that the Indians were spying on the commission out of their own interest in learning about Washington's attitudes to China.

Genuine or not, the sophisticated language the document was written in suggests it was created by someone with a clear grasp of India's bureaucratic style.