How has India reacted to attack in Kashmir and why are tensions in region so high?

Tensions between the arch-rivals India and Pakistan have escalated rapidly after the massacre of 25 Indian tourists and a Nepalese citizen in the disputed Himalayan Kashmir region on Tuesday, prompting warnings of a return to conflict. A previously unknown Islamic militant group calling itself the Resistance Front has claimed responsibility for the attack, which India immediately linked to Pakistan, although it did not publicly produce any evidence. Pakistan has denied any involvement. Among a string of punitive measures announced since Tuesday, India has downgraded diplomatic ties, suspended a crucial water-sharing treaty and revoked all visas issued to Pakistani nationals. In…