India and Pakistan are at it again.
The South Asian rivals are locked in another escalating confrontation over Kashmir, the ruggedly beautiful Himalayan territory they have tussled over for seven decades.
The countries have fought two wars over Kashmir, but the prospect of fresh hostilities is particularly worrisome because both now have nuclear weapons. Here's a look at the conflict and what could happen next.
What triggered the current crisis?
Tensions reached their highest point in years after four anti-India militants raided an army base inside the Indian-controlled portion of Kashmir on Sept. 18, killing 19 soldiers. India said the attackers came from Pakistan, which denied involvement.
India responded to the attack nine days later by sending commandos to strike militant outposts a short distance inside the Pakistani-administered part of Kashmir. Although the countries regularly trade fire across the border in contravention of a decades-old cease-fire, this was the first time India publicly acknowledged such a strike.
In recent days, India has accused Pakistan of violating the cease-fire more than two dozen times. On Thursday the Indian army said it killed three militants who fired on another military camp and four others attempting to cross into Indian-controlled Kashmir.
How did the Kashmir dispute begin?
When Britain gave up control of the Indian subcontinent in 1947, splitting it into a predominantly Hindu India and a predominantly Muslim Pakistan, the northern princely state of Kashmir — slightly larger than California — initially decided to remain independent.
Pakistan lay claim to Kashmir because most of its residents are Muslim. Shortly after independence, Pakistani raiders entered Kashmir, prompting the state's then-ruler to agree to join India if it sent troops to help him.
The ensuing war ended with Kashmir being divided into Indian- and Pakistani-controlled portions along a 435-mile cease-fire line. The countries went back to war in 1965 but fought to a stalemate.
A 1972 agreement designated the cease-fire line as the Line of Control, which remains in effect.
India controls eastern Kashmir and the southern Kashmir Valley, slightly more land than Pakistan, which holds the north and west. China also claims a chunk of northeast Kashmir, a high-altitude desert that is part of a long-running territorial dispute with India.
How many have died in the conflict?
Separatist groups that oppose Indian rule in Kashmir — including some that desire independence — have long done battle with the half-million Indian troops stationed there. India estimates that more than 47,000 civilians and police have been killed in the territory since 1989, although human rights groups say the toll is much higher.
Since July, after Indian paramilitaries gunned down a 21-year-old militant, the Kashmir Valley has seen its deadliest violence in six years.
More than 80 civilians have been killed in clashes with police, who have been accused of using excessive force. India blames Pakistan for stoking the violence, although Pakistan denies it.
Some Indian analysts saw the Sept. 18 raid on the army base as an attempt by Pakistan-based militants to test Indian Prime Minister Narendra Modi, who was already under international pressure over the deaths of demonstrators.
India and Pakistan have gone to the brink of war four times since 1987, but India has recently been reluctant to use force to avenge incursions in Kashmir, gambling that restraint earns it prestige globally.
Is the conflict likely to escalate?
Experts say it's unlikely. While the loudest voices in India demand revenge against Pakistan, analysts say neither country gains if things get worse.
India is the world's fastest-growing major economy, and Modi wants to focus on development, not defense. Several crucial state elections over the next year will hinge on how voters rate his Bharatiya Janata Party's handling of the economy.
Pakistan lacks India's conventional military capability. Its prime minister, Nawaz Sharif, is weak, and its powerful army chief is weighing retirement — an unsteady time for Pakistan to step into a major conflict with its more powerful neighbor.
Pakistan has denied that Indian commandos carried out "surgical strikes" after the Sept. 18 attack, characterizing the incidents as routine cross-border shelling. Hawks in India snigger at the denial, but Modi and other senior officials have not provided details that would confirm the operation, perhaps figuring that chest-thumping could make Pakistan more likely to retaliate.
The consequences of an all-out war between nuclear powers would be bleak: One study projected that if India and Pakistan exchanged fire from 100 nuclear weapons — less than half their combined arsenal — the war would kill 20 million people in a week and endanger 2 billion worldwide.
How are other countries responding?
The United States, which forged an alliance with Pakistan to fight terrorism, has recently grown closer to India.
Modi and President Obama have held several warm meetings and the bilateral trade and defense relationship is growing fast. Meanwhile, U.S. relations with Pakistan are souring, as shown by the Pentagon's decision to withhold $300 million in military funding because Islamabad failed to demonstrate it had taken action against terrorist groups attacking U.S. interests in Afghanistan.
The White House recently called on Pakistan to do more to rein in militant groups such as Jaish-e-Mohammad, which India blames for several attacks, including the raid on the army base.
Pakistan finds itself increasingly isolated. It had to postpone a South Asian summit scheduled for November in Islamabad after India, Bangladesh, Afghanistan and Bhutan all withdrew in protest of the army base attack.
Its most powerful friend, China, has said it "attaches importance to Pakistan's standpoint" on Kashmir. But according to reports, Beijing has quietly signaled to Islamabad that it must take a tougher line against militants.
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