An attack on tourists in India's Himalayan territory of Kashmir this week sparked a new crisis between nuclear armed South Asian neighbours India and Pakistan, with New Delhi blaming militants with "cross-border linkages" for the killings.

Indian authorities have detained at least 1,500 people in India-administered Kashmir after a militant attack killed 26 people this week, a top police officer told NPR.

In a further escalation, the two sides have repeatedly exchanged gun and artillery fire across the Line of Control that demarcates India-held Jammu and Kashmir from Pakistani-controlled Azad Kashmir,