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.

With tensions simmering, the militant attack has governments worried that India and Pakistan are once again on the brink of conflict. Here’s what you need to know as relations between them plunge to their lowest level in years.

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