India and Pakistan summon envoys after warships collide in the Arabian Sea

India and Pakistan called in each other's senior diplomats on 16 September after a collision the previous evening between PNS Hunain, a Yarmook-class corvette of about 2,600 tonnes, and a frontline Indian Navy destroyer in the North Arabian Sea.

Indian officials put the contact at roughly 120 nautical miles from the Gulf of Oman, in international waters, and identified the Indian ship as a Kolkata-class destroyer of more than 7,000 tonnes. Some Indian accounts name INS Kolkata. Others, citing the defence ministry, name INS Godavari on a surveillance patrol. Pakistan's Foreign Office named INS Kolkata. The discrepancy has not been cleared in public.

New Delhi's version is that Hunain closed at high speed from starboard, ignored warnings on Channel 16, and cut across the destroyer's bow. Ship logs seen by Indian officials, according to a News18 report, show no steering failure or emergency turn on the Pakistani ship before the impact. The Ministry of External Affairs said the conduct broke Article 10 of the April 1991 Agreement between India and Pakistan on Advance Notice on Military Exercises, Manoeuvres and Troops Movements, which requires naval units to keep at least three nautical miles apart. Charge d'Affaires Saad Ahmad Warraich was summoned in New Delhi. India's top diplomat in Islamabad was told to deliver the same protest.

Islamabad's version is almost the mirror image. The Foreign Office said the Pakistan Navy was running its biennial SEASPARK-26 exercise inside Pakistan's exclusive economic zone when the Indian ship made aggressive turns in close proximity. A security source in Islamabad claimed the Indian vessel and its helicopter had been trying to enter the exercise box since 7 September. Pakistan summoned the Indian charge d'affaires and rejected New Delhi's account. Hunain, Indian sources said, was damaged and headed for home port. The Indian ship continued its patrol. No deaths were reported.

First contact since last year's four-day fight

Reuters noted that this is the first overt military friction between the two navies since a four-day conflict last year that ended in a ceasefire. The last similar scrape at sea was in 2011, when PNS Babur brushed INS Godavari in the Gulf of Aden and tore a helicopter safety net.

Sandeep Unnithan, writing in India Today, compared Hunain's run to tactics the Chinese navy has used in the East and South China Seas: a smaller ship driving across the bow of a heavier unit to force it off station. A Kolkata-class destroyer that answered with its own aggressive turn would have produced a far worse result, he said. That reading is an Indian inference, not a finding both capitals accept.

What the 1991 text actually requires

The 1991 manoeuvre agreement is one of the few military confidence measures that survived the last three decades of crises. It is specific about distances and notice. It is silent on what happens when one side says the water is an exercise box and the other says it is high seas. That silence is now the legal argument. India says the contact was in international waters and that Hunain came inside three nautical miles. Pakistan says the Indian ship entered a notified exercise and made the dangerous turn.

Neither government has released radar plots, bridge audio or a joint inquiry. Until those appear, the only hard facts are the summonses, the names of the ships, the date, the approximate position, and the absence of casualties. Those facts are enough to put the two navies back into a crisis grammar they had not used at sea since last year's fighting. The next patrol in the same square of water will be run with that grammar in mind.