New Delhi, Oct. 20: Political activists Prashant Bhushan and Yogendra Yadav today released documents claiming to show that the Narendra Modi administration and the Congress are guarding known defence agents who have leaked official secrets, bribed military officers and even honey-trapped a BJP parliamentarian.

The defence ministry has refused comment but MP Varun Gandhi has threatened a defamation suit against Bhushan and Yadav, former Aam Aadmi Party stalwarts who now run the Swaraj Abhiyan, because of insinuations against him.

The documents are mostly letters and emails written by C. Edmonds Allen, a former associate of suspected arms middleman Abhishek Verma, son of former Congress Rajya Sabha members Shrikant and Veena Verma.

Abhishek is being investigated since 2006. He and his Romanian-born wife Anca-Maria Neacsu were jailed during the investigations, which are still continuing. They are now on bail. Having fallen out with Abhishek, the New York-based Allen has turned a whistleblower.

He has written to the Prime Minister, defence minister, national security adviser and the CBI director, forwarding the mails. He has sought punishment for Abhishek, the allegedly bribed officers and the MP, said to have been a member of the defence consultative committee in 2010.

A letter by Allen, dated September 16 this year and addressed to the Prime Minister, says Abhishek, his wife and an accomplice took photos of the MP "in compromising positions in return for information on the workings of the parliamentary defence committee".

Bhushan and Yadav said a former member of the Central Board of Direct Taxes had warned the Prime Minister's Office about this on May 30, 2014, days after Modi came to power. They said Allen's purported evidence had been pending with the government since August this year but no action had been taken.

One letter from Allen names a much-decorated retired air marshal and a wing commander who was posted in the naval war room. It says they conspired to procure and leak operational secrets to major defence companies, using both money and "foreign escorts".

Bhushan said that one of the beneficiaries of the naval war room leak in 2005 was also deeply involved in the deal to contract 36 Rafale combat jets, signed last month. French firm Thales is involved in the Rafale deal as well as the Rs 19,000-crore deal to make six Scorpene submarines in India that was awarded in 2006.

Denying the allegations, Varun said: "They (Yadav and Bhushan) did not substantiate a single allegation against me; I will take this head on."

On the letter that said he had been honey-trapped, the BJP Lok Sabha member from Sultanpur countered: "Does it provide a shred of evidence that any classified information was passed on to anyone? Members of the consultative committee on defence do not have access to confidential information, that is well known."

Varun said he had not met Abhishek since entering public life. "I last met Abhishek Verma when I was just out of college; when I was 21. His parents were Rajya Sabha MPs from the Congress."

He highlighted that neither Yadav nor Bhushan had taken his name at the news conference. To reporters' repeated questions about the identity of the MP, both had directed them to the documents they had circulated, saying his name was in Annexure E.

"They didn't want to name me because they feared a criminal defamation suit," Varun said.

Told that Yadav had threatened to release tapes if the government denied the allegations, Varun shot back: "They don't have any tapes."

Varun said the timing of the allegations --- when his performance in poll-bound Uttar Pradesh was being spoken about --- was suspicious but did not want to speculate.

Many social media users, however, wondered whether the "revelations" had anything to do with Varun's growing popularity in the heartland state.

Former Delhi minister and Aam Aadmi Party legislator Somnath Bharti tweeted that the allegations against Varun would be shocking "if true but time of revelation suggests that it could be an attempt 2 sideline him in UP elections".

Krishan Partap Singh, author of the political trilogy Raisina Series, tweeted: "I doubt the media wld hv dared broadcast letter incriminating Varun Gandhi without BJP's clearance. Varun Gandhi getting too popular in UP."

On Wednesday, Varun had refused to be drawn into the BJP's Ram temple politics despite being its representative from the state, drawing considerable flak from pro-BJP trolls.

Asked to comment on the temple issue, Varun was quoted by ANI as saying: "I practise the politics of the poor and rural India; I don't want to speak on such issues."