India announced on Monday that it had retaliated against “unprovoked” gunfire from Pakistan across their shared border for the fourth consecutive night, as it intensifies a manhunt for militants following last week’s deadly attack on tourists in Kashmir.

The attack, which occurred on April 22, claimed the lives of 26 people, many of them tourists. Indian authorities said two of the three suspected gunmen were Pakistani nationals, a claim Islamabad has denied, calling instead for an independent investigation.

The assault has triggered widespread anger and grief in India, accompanied by calls for firm action against Pakistan, which New Delhi accuses of funding and supporting terrorism in the disputed region of Kashmir.

Amid rising tensions, the two nuclear-armed neighbors have taken reciprocal measures: India suspended the Indus Waters Treaty, while Pakistan closed its airspace to Indian airlines, according to Reuters.