New Delhi -- Indian Air Force jets carried out "pre-emptive" strikes on Pakistani territory on Tuesday, stoking tension between the nuclear-armed neighbors. Pakistan called the attack a "grave aggression" and promised a "timely and effective response" by its own military.

India claimed the strikes hit "the biggest training camp" of the Islamic extremist group Jaish-e-Muhammad, killing "a very large number of terrorists," in Pakistan's Khyber Pakhtunwa Province.

The airstrikes came 12 days after a suicide car bomb attack by Jaish-e-Muhammad on Indian paramilitary soldiers in India's half of Kashmir. The terror attack left more than 40 soldiers dead and spiked the animosity between two nations which have fought over territorial rights to the Himalayan region of Kashmir for decades.

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India and Pakistan have fought three major wars since 1947, but there has been no major military confrontation since both nations gained nuclear weapons.

An Indian paramilitary solider fires tear gas shell towards Kashmiri protesters in Srinagar, Indian controlled Kashmir, Feb. 26, 2019. Kashmiri protesters were protesting against raids targeting purported key separatist leaders by Indian intelligence officers. AP

Indian Prime Minister Narendra Modi blamed Pakistan for the February 14 suicide attack in Kashmir -- one of the deadliest in decades -- and promised a "crushing response" in its wake. Pressure then mounted quickly on Modi, just days ahead of general elections in which he is seeking a second term, with demands for military action against the neighboring nation.

"I assure you, the country is in safe hands," Modi told a crowd of supporters at an election rally on Tuesday. "I pledge on this soil, I will not let the country die, I will not let the country stop. I will not let the country bend. It is my promise to Mother India; I will protect your honor."

A "non-military" missile strike?

Indian Foreign Secretary Vijay Keshav Gokhale called the strike a "non-military pre-emptive action, specifically targeted at the Jaish-e-Muhammad camp."

Gokhale may have used the unusual characterization to stress the point that India had not, and did not wish to, target Pakistan's own national military assets.

Indian media reports, citing anonymous Indian Air Force sources, said 12 Mirage 2000 fighter jets had dropped 1,000 kilogram (1,600 pound) bombs on the alleged Jaish-e-Mohammed camp in the early hours of Monday morning.

India said the strike was predicated by intelligence showing the terror group was planning more suicide attacks in India.

"In the face of imminent danger, a pre-emptive strike became absolutely necessary," Gokhale said. He added that the target, located on a hilltop in dense forest, was chosen with a "desire to avoid civilian casualties."

The purported camp was said to be headed up by Maulana Yousuf Azhar, the brother-in-law of Maulana Masood Azhar, the leader of Jaish-e-Muhammad and one of India's most wanted men. He is accused of planning several attacks against India, including a 2001 attack on India's parliament.

Pakistan vows to retaliate for "aggression"

Pakistani officials confirmed that Indian Air Force jets crossed into the country's territory, but in a series of tweets, military spokesman Maj. Gen. Asif Ghafoor said the Indian jets had dropped their bombs "in haste while escaping" from a "timely and effective response from Pakistan Air Force."

Ghafoor claimed the missiles came down in an "open area" and caused no material damage or casualties. He tweeted several photos allegedly of the spot where the bombs fell, one of them showing what appeared to be a missile part. The area did appear to be a wooded hilltop, but there was no sign in the photos of any infrastructure or human presence.

Payload of hastily escaping Indian aircrafts fell in open. pic.twitter.com/8drYtNGMsm — Maj Gen Asif Ghafoor (@OfficialDGISPR) February 26, 2019

Pakistan Foreign Minister Shah Mahmood Qureshi labelled the airstrikes an unwarranted "grave aggression by India," and said Pakistan had a "right to respond." He said Pakistan would respond "at a time and place of its choosing," noting that the country's military forces had been asked to be ready.

Qureshi said foreign media were welcome to visit the area where the Indian bombs dropped, and reiterated that they had caused no damage or casualties.

Indian media reports said the country's military was put on high alert to meet any response by Pakistan's air force.

Monday was not the first time India had carried out a limited military action against purported terrorist targets in Pakistan. In September 2016, in response to an attack on a border military base in Indian Kashmir that killed 19 soldiers, India carried out "surgical strikes" on Pakistan 10 days later. Again, Pakistan denied that India had inflicted any damage.