India and Pakistan have intensified their hostilities over the hotly contested Kashmir region following a massacre of 26 mostly Indian tourists, which New Delhi linked to Pakistan

NEW DELHI — A deadly attack on tourists in Indian-controlled Kashmir has again moved India and Pakistan closer to war as the two rivals downgraded diplomatic and trade ties, closed the main border crossing and revoked visas for each other’s nationals.

Indian officials said the army had a brief exchange of fire with Pakistani soldiers along their highly militarized frontier in the Himalayan region of Kashmir, as the nuclear-armed rivals ramped up tit-for-tat diplomatic offensive following a deadly attack on tourists in the disputed area.