Pakistani and Indian troops exchanged fire overnight across the Line of Control in disputed Kashmir, officials said yesterday, after the nuclear-armed nations unleashed a raft of measures against each other.

Relations have plunged to their lowest level in years, with India accusing Pakistan of supporting "cross-border terrorism" after gunmen killed 26 civilians in Pahalgam, the worst attack on civilians in contested Kashmir for a quarter of a century.

Syed Ashfaq Gilani, a government official in Pakistan-administered Kashmir, told AFP yesterday that troops exchanged fire along the Line of Control (LOC) that separates the two countries.

"There was no firing on the civilian population," he added.

India's army confirmed there had been limited firing of small arms that it said had been "initiated by Pakistan", adding it had been "effectively responded to".

Indian security forces yesterday intensifies a massive manhunt for those responsible for the killings on Tuesday -- with police naming two Pakistani nationals among the fugitive gunmen.

Armed with Unmanned Aerial Vehicles (UAVs) and drones, Indian security forces yesterday scoured the dense forests.

The security personnel drawn from army, paramilitary and Jammu and Kashmir police searched the dense jungles of the Pir Panjal range, overlooking Pahalgam and the Jammu-Srinagar national highway.

Indian officials said initial investigations into the attack indicate that the number of terrorists involved could range from five to seven.

At least two local militants aided them, they added.

Meanwhile, authorities in Indian Kashmir demolished the houses of two suspected militants, one a suspect in Tuesday's attack, reported Reuters , quoting an official.

Denying any involvement, Islamabad called attempts to link Pakistan to the Pahalgam attack "frivolous" and vowed to respond to any Indian action.

"Any threat to Pakistan's sovereignty and to the security of its people will be met with firm reciprocal measures in all domains," a statement said, after Prime Minister Shehbaz Sharif held a rare National Security Committee with top military chiefs.

Pakistan's Senate yesterday passed a resolution condemning a "campaign by the Indian government to malign the Pakistan government".

"I say to the whole world: India will identify, track and punish every terrorist and their backer," Indian Prime Minister Narendra Modi said Thursday.

"We will pursue them to the ends of the Earth."

UN spokesman Stephane Dujarric told reporters in New York that issues between the countries "can be and should be resolved peacefully through meaningful mutual engagement".

Kashmir has been divided between India and Pakistan since their independence in 1947, with both claiming the territory in full but governing separate portions of it.

Rebel groups have waged an insurgency in Indian-controlled Kashmir since 1989, demanding independence or a merger with Pakistan.

India's air force and navy both carried out military exercises Thursday.

Indian police say the three gunmen are members of the Pakistan-based Lashkar-e-Taiba group, a UN-designated terrorist organisation.

They offered a two-million-rupee ($23,500) bounty for information leading to each man's arrest.

A day after the attack, New Delhi suspended a water-sharing treaty, announced the closure of the main land border crossing with Pakistan, downgraded diplomatic ties, and withdrew visas for Pakistanis.

In response, Islamabad on Thursday ordered the expulsion of Indian diplomats and military advisers, cancelling visas for Indian nationals -- with the exception of Sikh pilgrims -- and closing the main border crossing from its side.

Pakistan also warned that any attempt by India to stop the supply of water from the Indus River would be an "act of war."

In reply, India's Water Resources Minister CR Paatil yesterday said New Delhi is working on measures to ensure that "not even a drop" of water goes to Pakistan.

"We will ensure that not a single drop of the Indus river's water reaches Pakistan," he said in a post on X.

India has formally informed Pakistan of its decision to keep the Indus Waters Treaty of 1961 in abeyance with immediate effect.

India's Secretary of Jal Shakti (Water Resources) Ministry Debashree Mukherjee wrote a letter dated April 24 addressed to her Pakistani counterpart, Syed Ali Murtaza, conveying New Delhi's decision, reports our New Delhi Correspondent.

Meanwhile, Indian Home Minister Amit Shah yesterday called up the chief ministers of all Indian states and asked them to ensure that no Pakistani stays in India beyond the April 27 deadline, sources said.

Meanwhile, Rahul Gandhi, the leader of the opposition in Lok Sabha, yesterday met Jammu and Kashmir Chief Minister Omar Abdullah in Srinagar to discuss the fallout of the Pahalgam terror attack on tourists. Rahul earlier interacted with the injured tourists at a hospital.

Pahalgam marks a dramatic shift in recent Kashmiri rebel attacks, which typically target Indian security forces.

Experts say that a military response may still be in the pipeline.

In 2019, a suicide attack killed 41 Indian troops in Kashmir and triggered Indian air strikes inside Pakistan, bringing the countries to the brink of all-out war.

"Whatever little land these terrorists have, it's time to reduce it to dust," Modi said on Thursday, after holding two minutes of silence in memory of those killed, all but one of whom was Indian.

India has taken its time to respond to past attacks.

The worst attack in recent years in Indian-run Kashmir was at Pulwama in 2019, when insurgents rammed a car packed with explosives into a police convoy, killing 40 and wounding 35.

Indian fighter jets carried out air strikes on Pakistan territory 12 days later.

Tuesday's assault happened as tourists enjoyed tranquil mountain views at the popular site at Pahalgam, when gunmen burst out of forests and raked crowds with automatic weapons.