Islamabad has threatened to suspend all agreements between the two countries, including the Simla Pact of 1972, which validates the Line of Control in Jammu and Kashmir and Ladakh, media reports said.

The Indian Government on Wednesday evening suspended the decades-old Indus Waters Treaty with Pakistan indefinitely as a part of some strict measures taken against Islamabad over the "cross-border linkages" that emerged during the investigation into the Pahalgam terror attack.

India has also asked all Pakistani nationals to leave the country by April 29 and suspended all visas, including medical ones and permits given to diplomats under the SAARC scheme.

In a tit-for-tat move, Pakistan also announced that it will reduce the Indian diplomatic staff at the High Commission to 30 persons.

India had announced the same on Wednesday. Both countries have now declared that their air force, naval diplomats, and support staff at the respective High Commissions are Persona Non Grata.

Following India's decision to suspend the Indus Waters Treaty, Pakistan said, "Any attempt to stop or divert the flow of water belonging to Pakistan as per the Indus Waters Treaty, and the usurpation of the rights of lower riparian will be considered as an Act of War and responded with full force across the complete spectrum of national power."

Pakistan now faces a grave situation after the water supply from the Indus River and its distributaries, including the Jhelum, Chenab, Ravi, Beas, and Satluj, has been stopped.

These rivers supply the water requirements for Pakistan and impact tens of millions of people in the neighbouring country.

The Indus Waters Treaty was signed between India and Pakistan on September 19, 1960, with the World Bank brokering the agreement. That treaty remained steady despite the three wars between India and Pakistan - in 1965, 1971, and 1999, but is now suspended indefinitely.

"Pakistan shall exercise the right to hold all bilateral agreements with India, including but not limited to Simla Agreement in abeyance, till India desists from its manifested behaviour of fomenting terrorism inside Pakistan," Islamabad said.

This announcement is significant as the Simla Agreement, signed after the 1971 war, makes provision for the ceasefire line to be known as the Line of Control (LoC), which is where the armies of the two nations are stationed. Should Pakistan suspend the Simla Agreement, it will raise a question on the validity of the Line of Control.

Measures taken by Pakistan in its response to India's actions

Pakistan shall close down the Wagah Border Post, with immediate effect. All cross-border transit from India through this route shall be suspended, without exception.

Those who have crossed with valid endorsements will have to return through that route immediately by April 30.

Pakistan has also suspended all visas under SAARC Visa Exemption Scheme (SVES) issued to Indian nationals and deems them cancelled with immediate effect, with the exception of Sikh religious pilgrims. Indian nationals currently in Pakistan under SVES are instructed to exit within 48 hours, less Sikh pilgrims.

Pakistan's airspace will be closed with immediate effect for all Indian owned or Indian operated airlines.

All trade with India, including to and from any third country through Pakistan, is suspended forthwith.

The Pakistani statement also said that its "armed forces remain fully capable and prepared to defend its sovereignty and territorial integrity," adding that it will "never allow anyone to transgress its sovereignty, security, dignity and their inalienable rights".

Pahalgam Massacre

Twenty-six tourists died after terrorists identified them as non-Muslims and gunned them down in Baisaran meadows, a popular destination in Pahalgam.

World leaders, including US President Donald Trump and Russian President Vladimir Putin, condemned the attack.

The terrorists, who were apparently in camouflage, reportedly asked the victims to chant Islamic verse, pull down their pants to check circumcision in a bid to confirm their Hindu identities before gunning them down. One Nepali national was among those killed.