India conducted a major preemptive strike on a Jaish-e-Mohammed training camp early Tuesday, killing a "very large number" of terrorists, trainers and senior commanders, Indian Foreign Secretary Vijay Gokhale said.

He said the "intelligence-led operation" on the Pakistan-based terror group's biggest training camp in Balakot became "absolutely necessary" as it was planning more suicide attacks in India. JeM claimed responsibility for the February 14 Pulwama attack on a CRPF convoy in which 40 soldiers were killed.

Sources told PTI that Prime Minister Narendra Modi has briefed President Ram Nath Kovind and Vice President M Venkaiah Naidu about Tuesday's strike.

It was not clear if the strike was on Balakote in Pakistan occupied Kashmir or Balakot in Pakistan's Khyber Pakhtunkhwa province.

Gokhale also did not give details of how the attacks were carried out or confirm earlier reports by sources that Mirage aircraft were used to drop bombs in the operation.

"Credible intelligence was received that JeM was attempting another suicide terror attack in various parts of the country, and the fidayeen jihadis were being trained for this purpose," Gokhale told the media.

In the face of imminent danger, a preemptive strike became "absolutely necessary", the foreign secretary said.

Addressing the media at 11.30 am, he said the strike had been carried out by a "short while ago" and further details were awaited.

"In this operation, a very large number of JeM terrorists, trainers, senior commanders and groups of jihadis who were being trained for fidayeen action were eliminated," he said.

The facility at Balakot, located in a thick forest on a hilltop far away from civilian presence, was headed by Maulana Yousuf Azhar, alias Ustad Ghouri, the brother-in-law of JeM chief Masood Azhar, he said, reading out from a statement.

The statement did not say if Yousuf Azhar was among those killed.

"The Government of India is firmly and resolutely committed to taking all necessary measures to fight the menace of terrorism," the foreign secretary said.

The selection of the target, he said, was conditioned by the desire to avoid civilian casualties.

India, Gokhale said, expects Pakistan to dismantle all terror camps, including those of the JeM.

" India has been repeatedly urging Pakistan to take action against the JeM to prevent jihadis from being trained and armed inside Pakistan. Pakistan has taken no concrete actions to dismantle the infrastructure of terrorism on its soil," he said.

Earlier in the day, government sources said Mirage 2000 combat jets of the Indian Air Force bombed terror camps at multiple locations across the Line of Control in the Pakistani side. They said jets pounded the camps in Balakot, Muzaffarabad and Chakoti.

However, there was no independent confirmation of these reports and Gokhale made it clear that only one camp was struck in Balakot without mentioning the Mirage 2000 jets.

The JeM has been active in Pakistan for the last two decades and has its headquarters in Bahawalpur in Pakistan's Punjab province, Gokhale said in the statement.

He pointed out that the organization is proscribed by the UN and has been responsible of a series of terrorist attacks, including on the Indian Parliament in December 2001 and the Pathankot airbase in January 2016.

"Information regarding the location of training camps in Pakistan and PoJK has been provided to Pakistan from time to time. Pakistan, however, denies their existence. The existence of such massive training facilities capable of training hundreds of jidhadis could not have functioned without the knowledge of Pakistan authorities," he said.

Though India has repeatedly urged Pakistan to take action against the JeM to prevent jihadis from being trained and armed inside Pakistan, Islamabad has taken no concrete action "to dismantle the infrastructure of terrorism on its soil", Gokhale said.

In Islamabad, Pakistan Foreign Minister Shah Mahmood Qureshi called an "emergency meeting" at the Foreign Office for consultations, sources said.

Qureshi will meet Pakistan Prime Minister Imran Khan after the meeting in which he will discuss the security situation with high-level officials, they said.

In an early morning tweet, Major General Asif Ghafoor, director general of the Inter-Services Public Relations (ISPR), the media wing of the Pakistan Army, said Indian aircrafts intruded from the Muzaffarabad sector.

"Facing timely and effective response from Pakistan Air Force released payload in haste while escaping which fell near Balakot. No casualties or damage," Ghafoor said in a tweet.

"Indian Air Force violated Line of Control Pakistan. Pakistan Air Force immediately scrambled. Indian aircraft gone back," he claimed.