Take two nuclear-armed rivals. Mix in a history of war and a disputed region that's been the site of a decadeslong rebellion. Now add a deadly militant attack against civilians that risks boiling those tensions over.

That's where things stand between India and Pakistan afteran April 22 attackthat killed mostly Indian nationals in Jammu and Kashmir sent tensions between the two countries skyrocketing. India has accused Pakistan of supporting cross-border terrorism, but the Pakistani government denies it was behind the attack that killed 26 civilians.

New Delhi and Islamabad have since carried out tit-for-tat punishments following the incident, including downgrading diplomatic and trade ties, closing the main border crossing, and revoking visas for each other's nationals.

The Pakistani government later said it would consider it "an act of war" if India followed through on a threat to block the flow of crucial rivers as punishment for the deadly incident.

On April 26, Pakistan called for a "neutral" investigation into the killings, saying it "remains committed to peace" ad that it was willing to cooperate with any probe.

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Indian and Pakistani forces on April 25exchanged gunfirefor the second straight day along the Line of Control (LOC) separating the two countries in disputed Kashmir, which is split between them, claimed by both in its entirety, and was at the center of two of the three wars that New Delhi and Islamabad have fought against each other.

With tensions simmering, the episode has governments worried that India and Pakistan are once again on the brink of conflict.

Here's what you need to know as relations between them plunge to their lowest level in years.

What Happened At The Pahalgam Attack In Kashmir?

On April 22, gunmen carried out the worst attack on civilians in contested Muslim-majority Kashmir for a quarter-century.

New Delhi immediately linked Pakistan to the attack near the picturesque town of Pahalgam in the Himalayas, although it did not publicly produce any evidence. This was followed by punitive measures against Pakistan, which Islamabad later responded to with countermeasures of its own.

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An obscure group calling itself the Resistance Front has claimed responsibility for the attack. Indian officials say it is a proxy for the Pakistan-based Lashkar-e-Taiba.

Islamabad denied involvement, accusing India of failing to provide proof.

A manhunt is under way for three suspects involved in the attack -- one Indian national and two Pakistanis -- and the Indian Army says it launched "search and destroy" operations to find them across the Kashmir Valley.

How Does The Attack Risk Escalating Tensions Between India And Pakistan?

India and Pakistan have each laid claim to Kashmir since war broke out following the British partition of the subcontinent in 1947. Border skirmishes have long created instability in South Asia.

The two archrivals have also fought three wars over Kashmir, where armed insurgents have resisted Indian rule for decades, with many Muslim Kashmiris supporting the rebels' goal of uniting the territory, either under Pakistani rule or as an independent country.

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India has accused Pakistan of fomenting violence there over the decades, a charge denied by Islamabad. Tens of thousands of civilians, rebels, and government forces have been killed in the conflict over the years.

The last major militant assault in the Indian part of Kashmir took place in 2019, when dozens of Indian security personnel were killed. After that attack, India launched an air battle that stopped just short of all-out war.

Following the Pahalgam attack, commentary in Indian media, which is largely aligned with the government of Prime Minister Narendra Modi, and talk among the country's political leadership has leaned toward launching a military strike on Pakistan.

"We will not only reach out to those who have carried out this incident. We will also reach out to those who, sitting behind the scenes, have conspired to commit such nefarious acts on the soil of India," Indian Defense Minister Rajnath Singh said on April 23.

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India also began large-scale air and naval drills on April 24, which analysts say could pave the way for military action.

"There are many imponderables Modi must deal with, including the significant capabilities of the Pakistan Army," Indian political analyst C. Raja Mohanwrote in the Indian Express. "But given the horrific nature of the attack and the outrage that has convulsed the nation -- the victims came from 15 states across India -- the PM may have no option but to explore some major risks."

Himayat Ullah, a political scientist at Quaid-e Azam University in Islamabad, told RFE/RL he believes both New Delhi and Islamabad are aware of the risks of further escalation and will aim to avoid "a full-fledged war" but that "to show its people, India and the Modi government may go for some limited actions."

Why Is India Suspending The Water Treaty Significant?

The day after the attack, India announced the suspension of the six-decade old Indus Waters Treaty, which shares water between the two countries and could be a flashpoint as tensions continue to boil.

In response, Pakistan warned any Indian attempt to stop or divert the flow of water between them would be considered an "act of war."

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The Indus Water Treaty, brokered by the World Bank in 1960, allows for sharing the waters of a river system that is a lifeline for both countries. Pakistan described it as a "vital national interest" and the treaty is essential for supporting agriculture and hydropower in the country of 240 million people.

The treaty has survived two wars between the countries, in 1965 and 1971, and a major border skirmish in 1999. Its potential unraveling now marks a rupture with huge symbolic and strategic weight.

Islamabad, meanwhile, warned it could suspend the Simla Agreement, a significant peace treaty signed after the 1971 India-Pakistan war that ended in Bangladesh splitting from Pakistan and becoming an independent nation.

Under that agreement, India and Pakistan established the LOC, previously called the Cease-fire Line, a highly militarized de-facto border that divides Kashmir between them.

What Happens Next?

Governments and analysts are closely watching the unpredictable situation between the nuclear-armed neighbors.

Following theexchange of small-arms fire in Kashmir, the United Nations called for "maximum restraint" between the two countries.

"We very much appeal to both the governmentsto exercise maximum restraint, and to ensure that the situation and the developments we've seen do not deteriorate any further," UN spokesman Stephane Dujarric said on April 24.

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On the diplomatic front, Indian Foreign Minister Vikram Misri briefed envoys from 25 countries, including key G20 partners, Gulf states, and also China, who is a close partner of Pakistan's and has had strained ties with New Delhi in recent years.

The broader outreach, as well as Beijing's inclusion, is seen as a move to build global consensus toward India's side as it weighs its response.

Another factor is that diplomatic relations between India and Pakistan were already weak before the latest measures and countermeasures announced following the attack. Pakistan expelled India's envoy and has not posted its own ambassador in New Delhi since India revoked the semi-autonomous status of Kashmir in 2019.

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Khalid Sultan, a professor at the University of Islamabad, told RFE/RL that the risks of escalation are real and the tense situation means things could also spiral inadvertently.

But he adds that "international pressure" has helped avert outright war between India and Pakistan in the past and New Delhi's active diplomacy points toward a more limited Indian response.

Praveen Swami, the national-security editor at the Indian daily newspaper The Print, told RFE/RL New Delhi's response will be determined on the evidence and proof it is able to share with other governments and the public.

"If India finds proof about the involvement of Lashkar-e-Taiba, then there will be some reaction. But without that, even a strike or a limited war remains unlikely."