India accused its fellow nuclear power Pakistan of being behind a terrorist suicide bomb attack in Kashmir that killed at least 44 Indian security officers on Thursday, reportedly marking the deadliest attack in the disputed region in decades.

Thursday’s incident intensified the hostility between nuclear-armed Pakistan and India. In a speech in the wake of the attack, Indian Prime Minister Narendra Modi declared, “We will give a fitting, jaw-breaking reply, our neighbor will not be allowed to destabilize us,” the Independent reveals.

Modi said the Indian government security forces have “total freedom” to deal with the militants, the Associated Press (AP) notes.

“Security forces have been given permission to take decisions about the timing, place, and nature of their response,” he also said.

Indian foreign secretary Vijay Gokhale summoned Pakistan’s ambassador in New Delhi and “issued a strong demarche” over the attack, the Independent reported, citing an unnamed Indian government source.

India and its rivals Pakistan and China all claim ownership of the Muslim-majority Kashmir region in the Himalayas.

China largely stays in the shadows of the dispute, mainly backing the position of its ally Pakistan. A border known as the Line of Control (LOC) divides the regions controlled by Pakistan and India.

Despite a 2003 ceasefire, tensions between the two regional rivals have escalated in recent years with repeated clashes between them along the LOC. Over 500 casualties last year in just the India-administered portion of Kashmir in the Himalayas reportedly made 2018 the deadliest year in the area in almost a decade.

The U.S.-designated terrorist group Jaish-e-Mohammad (JeM), based in Pakistan, claimed responsibility for the suicide bombing attack on a security convoy on Thursday.

India reportedly claimed to have “incontrovertible evidence” of Pakistan’s involvement, an accusation rejected by Islamabad.

Pakistan issued a statement condemning the attack and denying any links to JeM.

In a statement, the White House urged Pakistan “to end immediately the support and safe haven provided to all terrorist groups operating on its soil, whose only goal is to sow chaos, violence, and terror in the region.”

India urged the United Nations to impose sanctions on JeM leader Masood Azhar, a move blocked by Pakistan’s ally China.

“I appeal to all nations to come together and strengthen their efforts and resolve to put an end to menace of terrorism,” PM Modi proclaimed, according to the Independent. “I thank all the nations who have supported us and condemned this incident in the strongest of terms.”

Thursday’s attack took place on the Indian-administered portion of Kashmir along the heavily guarded Srinagar-Jammu highway.

“A car laden with explosives overtook the convoy and rammed into a bus full of paramilitary officers,”

the Independent revealed.

“The blast was so powerful that one cannot recognize whether the vehicle was a bus or a truck. Just pieces of mangled steel remain,” Sanjay Sharma, a spokesperson for local police, reportedly said.

In Kashmir, the conflict between India and Pakistan has reportedly killed about 70,000 people since 1989.

While India accuses Pakistan of backing Islamic terrorists in Kashmir, Islamabad blames New Delhi of violently oppressing pro-Pakistan separatists who are fighting for independence or in favor of a merger with Pakistan.

Pakistan and India have already fought three wars over the region, in 1947, 1965, and 1999