India says it will shut a key land border with Pakistan and stall a water sharing treaty as part of a round of punitive measures against its neighbor, following a deadly attack in the disputed Himalayan region of Kashmir.

Foreign Secretary Vikram Misri said during a press briefing on Wednesday that “cross-border linkages” to the attack had been revealed in a security cabinet meeting, before citing a raft of measures that India would be taking against Pakistan.

Misri announced India would close the main land border at Attari-Wagah “with immediate effect.”

Pakistan relies heavily on the crossing for trade and is more dependent on it than India.

Misri further said defense, military, naval and air advisers at the Pakistani High Commission in New Delhi “are declared persona non grata”. They will have one week to leave India.

India would be withdrawing its advisors from the Indian High Commission in Islamabad, he added. 

“India will be withdrawing its own defense, navy and air advisers from the Indian High Commission in Islamabad.”

Under the punitive measures, Pakistani nationals would not be allowed to travel to India under a regional visa exemption scheme — and that Pakistani nationals in India traveling as part of it had 48 hours to leave the country.

India has suspended an old water sharing treaty with Pakistan.

“The Indus Waters Treaty of 1960 will be held in abeyance with immediate effect, until Pakistan credibly and irrevocably abjures its support for cross-border terrorism”, Misri was quoted as saying.

The treaty’s suspension could mean Pakistan faces severe water shortages. Pakistan is heavily dependent on the water from the Indus River and its tributaries for agriculture and drinking water.

Security in the Himalayan region of Kashmir has been beefed up since Tuesday’s attack, which resulted in the death of at least 26 people, with another 17 injured.

Tens of thousands of security forces were deployed to patrol the disputed Muslim majority region.

Cars were searched at checkpoints, as the military and police carried out missions to locate the attackers.

Prime Minister Narendra Modi had cut short his trip to Saudi Arabia and returned to New Delhi on Wednesday following the deadly assault. 

Modi was briefed by National Security Adviser Ajit Doval and Foreign Minister S. Jaishankar upon his arrival at the airport.

The April 22 attack came at a time when US Vice President JD Vance was visiting India on a four-day trip.

The violence was one of the deadliest episodes in a long history of conflict in the disputed Himalayan region that is divided principally between India and Pakistan.

The last major assault in the region took place in 2019, when a suicide bomber killed 40 members of Indian security forces.

Nuclear-armed arch-rivals India and Pakistan have long accused each other of backing forces to destabilize the other, and New Delhi says Islamabad backs the gunmen behind the insurgency.

Islamabad denies the allegation, saying it only supports Kashmir’s struggle for self-determination.

Pakistan’s Foreign Minister Ishaq Dar said Prime Minister Shehbaz Sharif would hold a meeting of the National Security Committee on Thursday to respond to India’s statement.