Pakistan and India hint at imminent military action over Kashmir. A look at the nuclear rivals

ISLAMABAD, Pakistan — A deadly attack on tourists in the disputed Kashmir region last week has spiked tensions between India and Pakistan. India accuses Pakistan of backing the massacre, a charge Pakistan denies.

The nuclear-armed neighbors have downgraded diplomatic ties, threatened to suspend key treaties and expelled each other's nationals. It's the biggest breakdown in relations since 2019, when a suicide car bombing killed 40 Indian soldiers in Kashmir. India blamed Pakistan, and Pakistan rejected the accusation.

India has hinted at the possibility of an imminent but limited military strike. Pakistan says it would respond militarily.

A look at the countries' nuclear capabilities, and what might lie ahead:

Both have nuclear weapons, but as a deterrent

India and Pakistan have built up nuclear arsenals over the years. But their purpose is to stop wars, not start them.

India has a ''no first use'' policy. That means it will only retaliate with nuclear weapons if there is a nuclear attack on Indian forces or Indian territories.

Pakistan has a different policy, full spectrum deterrence, aimed at using tactical nuclear weapons to counter nuclear threats and conventional military attacks from its bigger, stronger and richer regional rival.

Pakistan has not ruled out using nuclear weapons first if it feels an existential threat. But Pakistan can ill afford to initiate nuclear war with India because of its neighbor's superior firepower. It has lost three conventional wars in the past.

Instead, Pakistan uses its nuclear arsenal to deter India from invasion or massive attack.

Neither has details about the other's arsenal

Neither country knows what nuclear weapons the other has or how many. India conducted its first nuclear test in 1974. Pakistan carried out its first in 1988.

Thinktanks suggest Pakistan has 170 warheads while India has 172. Some analysis indicates that Pakistan could have more, around 200.

Despite decades of hostility and suspicion, India and Pakistan are signatories to a pact that bars them from attacking each other's nuclear facilities.

As part of the Prohibition of Attack against Nuclear Installations and Facilities, the two sides exchange lists of their nuclear facilities and installations each January. They have exchanged lists for 34 consecutive years.

However, neither country is a signatory to the global Non-Proliferation Treaty aimed at preventing the spread of nuclear weapons and weapons technology.

Both prefer limited strikes on specific targets

Flare-ups between India and Pakistan have seen targeted attacks and reprisals, escalating slowly while giving each side the option to step back and defuse. Border skirmishes are common.

But there is huge domestic pressure on India to respond this time because most of the victims last week were Indian.

In 2019, following the suicide car bombing, there was a predawn airstrike from India that it said targeted a terrorist training camp in Pakistan. Pakistan later said it shot down two Indian warplanes in Kashmir and captured a pilot. The pilot was eventually released and the situation began to normalize.

But the episode showed that India was willing to enter Pakistani airspace and launch strikes, setting a new threshold for retaliation.

In the current crisis, the two sides have yet to make a dramatic move. Pakistan has reported seeing Indian fighter jets over its airspace, and has shot down spy drones that it says belong to India.

Retaliation from either country is likely to be along the Line of Control, the de facto border dividing Kashmir, to target army infrastructure or militant facilities. The tactic carries the risk of miscalculation because any casualties could aggravate domestic sentiment.

The international community is more involved

With wars in the Middle East and Ukraine, and a world in economic chaos, the international community has little appetite for a war in South Asia.

U.S. Secretary of State Marco Rubio has said he will reach out to India and Pakistan and urged other foreign governments to step in and calm things down.

Pakistan's wealthy allies in the Gulf have expressed their desire for stability and security, while India has contacted G7 members about the crisis.

China, the most important player in the region, has urged both sides to show restraint. The United Nations has also called on Pakistan and India to deescalate. In short, nobody wants this.