By Shivam Patel and Fayaz Bukhari SRINAGAR, India (Reuters) -Indian Prime Minister Narendra Modi vowed on Thursday to pursue, track and punish terrorists and their backers in a strong reaction to a deadly militant attack on tourists in Kashmir,

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.

Relations between India and Pakistan are cratering following a deadly attack in the disputed Himalayan region of Jammu and Kashmir that left more than two dozen tourists dead, raising fears of military escalation between the nuclear-armed rivals.