India accused Islamabad of supporting "cross-border terrorism." Pakistan has denied the accusation and a previously unknown militant group calling itself Kashmir Resistance has claimed responsibility for the attack.

India and Pakistan both claim Kashmir in full but control it only in parts. Since India's partition and the creation of Pakistan in 1947, the nuclear-armed neighbours have fought wars over the territory.

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.