Troops from Pakistan and India exchanged fire in disputed Kashmir for a third night in a row, officials said Sunday, as relations between the nuclear-armed rivals plunged to their lowest level in years.

A day after the U.N. appealed for restraint following Tuesday's deadly attack in Indian-administered Kashmir, India reported an exchange of fire across the de facto border in the disputed region.

The nuclear-armed rivals ramped up tit-for-tat diplomatic offensive following a deadly attack on tourists in Pahalgam.