India issues veiled nuclear threat to Pakistan with hint it could abandon 'no first use' policy

'What happens in future depends on the circumstances,' defence minister says of Delhi's nuclear posture

India appears to have issued a veiled threat to Pakistan when its defence minister said the country's continued nuclear commitment to "no first use" would "depend on the circumstances".

The comment by Rajnath Singh introduces a level of ambiguity to a core national security doctrine, analysts said.

It comes amid tensions between the two countries which have increased following India's move to revoke autonomy in the disputed region of Kashmir, the cause of two of their three wars.

On Thursday, Pakistan's army said three of its soldiers were killed in cross-border shelling by India, and that five Indian soldiers were also killed. Delhi confirmed the exchanges of fire, but denied the deaths of its soldiers.

In February, Indian and Pakistani fighter jets clashed over the Kashmir region.

In a visit to Pokhran in western India, defence minister Rajnath Singh paid tribute to late former prime minister and revered leader of the ruling Hindu nationalists, Atal Behari Vajpayee, for making India into a nuclear power.

"Pokhran is the area which witnessed Atal Ji's firm resolve to make India a nuclear power and yet remain firmly committed to the doctrine of 'no first use'," he said.

"India has strictly adhered to this doctrine. What happens in future depends on the circumstances."

India declared itself a nuclear weapons power after conducting underground tests in Pokhran in 1998. Long-time rival Pakistan responded with its own tests shortly afterwards. Since then, nuclear experts say the rivals have been developing nuclear weapons and the missiles to deliver them.

At the time of the tests, India said it needed a deterrent against nuclear-armed China but it has also long been concerned about Pakistan's nuclear capabilities.

Shekhar Gupta, a political commentator and defence expert, said the government appeared to have an open mind on the issue of "no first use" of nuclear arms and the comments could be aimed at Pakistan, which has said previously it needed to develop small nuclear weapons to deter a sudden attack by India.

"Rajnath Singh is measured and not given to loose talk or bluster. He isn't signalling a shift, but an open mind on the NFU (No First Use) inherited from Vajpayee's Nuclear Doctrine," he said on Twitter.

Vipin Narang, a nuclear affairs expert at MIT in the United States, said that Singh's comments were a sign the policy on "no first use" could change in the future.

"Make no mistake: this is by far the highest official statement –​ from the [defence minister's] mouth directly - that India may not be forever bound by No First Use," Mr Narang said on Twitter.