The Congress said its app was connecting to a "membership" site that was "dysfunctional" and being wrongly circulated. "We found that Congress supporters go for direct membership and prefer offline," said Abhishek Manu Singhvi, Congress leader.

The BJP's Sambit Patra shot back: "For them IT means India Theft." He alleged that the Congress app sends data to Singapore servers which can be accessed easily.

The political crossfire has erupted in the middle of revelations that the personal data of thousands Facebook users was compromised and manipulated by disgraced research group Cambridge Analytica to help political parties.

A security researcher who has previously highlighted some vulnerabilities in the Aadhaar national ID card project and who tweets under the pseudonym Elliot Alderson, caused a flurry on Saturday with tweets saying the Narendra Modi app was sending, without consent, personal user data to a third-party domain that was traced to an American company.

Alderson on Sunday posted that the app had "quietly" updated its privacy policy after his previous tweets.

Taking aim at the PM, Rahul Gandhi tweeted: "Hi! My name is Narendra Modi. I am India's Prime Minister. When you sign up for my official app, I give all your data to my friends in American companies. Ps. Thanks mainstream media, you're doing a great job of burying this critical story, as always."

On Monday, the Congress president took it up a notch and tweeted: "Modi's NaMo App secretly records audio, video, contacts of your friends and family and even tracks your location via GPS. He's the Big Boss who likes to spy on Indians."

The BJP in turn lashed back after the same security researcher highlighted that the Congress app was transmitting the personal data of those that signed up in an unsecured format.

Smriti Irani, in a series of derisive posts, said Rahul Gandhi now knows what the NCC (National Cadet Corps) is thanks to the NaMo app. "Ye kya RahulGandhi ji it seems your team is doing the opposite of what you asked for. Instead of #DeleteNaMoApp, they have deleted the Congress App itself."