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.

The United Nations has urged India and Pakistan to exercise "maximum restraint" after they ramped up a tit-for-tat diplomatic offensive following a deadly attack on tourists in Indian-controlled Kashmir.

The nuclear-armed rivals, which both claim Kashmir and administer separate parts of it, are at a dangerous crossroad after Tuesday’s militant attack, analysts said.