Congress leader P Chidambaram on Monday took a swipe at IT Minister Ashwini Vaishnaw over his statement in Lok Sabha on the alleged illegal surveillance using Pegasus software and said it is unfortunate that the minister has started his innings on the "wrong foot".

In a series of tweets, Chidambaram said the minister should answer if the government acquired the Pegasus software/spyware.

"NSO Group, the owner of Pegasus, has said that 'NSO sells its technologies solely to law enforcement and intelligence agencies of vetted governments.' It is unfortunate that Minister Vaishnaw has started his innings on the wrong foot," he tweeted.

"The Minister should answer a simple question: Did the government acquire the Pegasus software/spyware?" he added.

Vaishnaw, in a suo motu statement in Lok Sabha, categorically rejected the allegations of snooping on politicians, journalists and others using Pegasus software, and asserted that illegal surveillance was not possible with checks and balances in the country's laws.

He said the media reports on alleged snooping published a day before the start of the Monsoon Session of Parliament "cannot be a coincidence" and stressed that there is "no substance" behind the sensationalism.

"The press reports of 18th July 2021 also appear to be an attempt to malign the Indian democracy and its well-established institutions," Vaishnaw said in his first statement in Parliament as a minister.

The minister, however, did not specify whether the Indian government was using Pegasus spyware developed by Israeli company NSO.

Chidambaram said, "In his statement the Minister has omitted to quote the crucial part of Pegasus' statement. The services that are 'openly available to anyone, anywhere, and anytime' refer to HLR Lookup services, not to Pegasus."

The former Union minister was referring to the statement given by the Israeli company to a group of media organisations that broke the story across the globe.

The Congress has demanded a thorough, independent probe into the matter and immediate sacking of Home Minister Amit Shah.