Nuclear experts believe that India may be rethinking their policy of "no first use" (NFU) of nuclear weapons - a move that could be alarming for neighbour Pakistan.

The assessment by analysts is based on statements issued in the recent past by Indian political leaders, including former defence minister Manohar Parrikar.

Talks about a possible change in New Delhi' nuclear policy comes after a recent presentation by Vipin Narang of Massachusetts Institute of Technology at the Carnegie International Nuclear Policy Conference in Washington DC. Narang in his presentation said that it appeared Indian authorities were likely to abandon the older nuclear policy to replace it with a new one that allowed a preemptive strike in threatened by a war. This has generated attention in the South Asian news media.

''India's opening salvo may not be conventional strikes trying to pick off just Nasr batteries in the theatre, but a full 'comprehensive counterforce strike' that attempts to completely disarm Pakistan of its nuclear weapons so that India does not have to engage in iterative tit-for-tat exchanges and expose its own cities to nuclear destruction,'' Narang said, according to the Times of India newspaper.

He also said there was increasing evidence that India will not allow Pakistan to go first.

"It's very scary because all the 'first-strike instability' stuff is real," Narang was quoted as saying by the New York Times.

Narang's deductions reportedly came from Parrikar questioning the existing nuclear doctrine in a speech made in November 2016. He had said that he was wondering why the country should continue to follow the "no-first use policy" with regard to nuclear weapons.

India Pakistan relations missile test
Nuclear experts have hinted India may reconsider changing its "no first use" policy for nuclear weapons as Pakistan says it comes as no surprise - File Photo Adnan Abidi/Reuters

The speculation also took into consideration former Indian Foreign Secretary Shivshankar Menon's memoir in which he wrote: ''There is a potential gray area as to when India would use nuclear weapons first'' against a nuclear-armed adversary.

Menon recently told Business Standard newspaper that India's nuclear doctrine has 'far greater flexibility than it gets credit for'.

However, Pakistani defence experts have branded India's nuclear doctrine as a sham and said that the revelation has come as no surprise.

Taking a dig at Narang's assessment, former Pakistani diplomat and nuclear negotiator Zamir Akram said: "For Pakistan, these disclosures do not come as a surprise since Indian NFU is really a sham and political rhetoric.

"By spilling the beans, Narang has only validated Pakistan's deterrence policy.''