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.

India and Pakistan troops exchanged fire in the Jammu and Kashmir region on Friday, according to officials in New Delhi, as relations between the nuclear-armed neighbors continue to plummet after a deadly attack on tourists this week.

Pakistan called India's actions “irresponsible" and canceled visas for Indian nationals, suspended all trade with India and closed its airspace to Indian aircraft.