Dhaka, June 27 -- As India's defence chief attended an international security conference in Singapore in May, soon after India and Pakistan fought what many in South Asia now dub "the four-day war", he had a simple message: Both sides expect to do it all again.

It was a stark and perhaps counterintuitive conclusion: the four-day military exchange, primarily through missiles and drones, appears to have been among the most serious in history between nuclear-armed nations.

Indeed, reports from both sides suggest it took a direct intervention from US Secretary of State Marco Rubio to halt an escalating exchange of drones and rockets.

Speaking to a Reuters colleague in Singapore, however, Indian Chief of Defense Staff General Anil Chauhan d...