Why have tensions escalated between India and Pakistan?

India has launched a missile attack on Pakistan and the territory Islamabad administers in Kashmir, killing at least 26 civilians, Pakistani officials have said.

India said it struck nine Pakistani sites early on Wednesday that provided “terrorist infrastructure”, and from which attacks against it were orchestrated.

But Pakistan’s defence minister said all the areas hit were civilian places, not militant camps.

One hit the Subhan Mosque in the city of Bahawalpur in Pakistani Punjab, killing 13 people including a child, according to Zohaib Ahmed, a doctor at a nearby hospital.

Meanwhile, an Indian police official said 10 people have been killed and 48 injured in Pakistani shelling of Indian administered Kashmir, while a Pakistan military spokesperson has also claimed five Indian jets were shot down over Kashmir, but this has not been verified.

Follow live: Dozens killed as Pakistan and India exchange fire in disputed Kashmir

It all marks the worst fighting in more than two decades between the countries, in a region that has long been at the heart of their conflicts.

Here’s what you need to know.

India’s strikes retaliation for ‘terror attack’

India’s strikes were in retaliation for an attack on 22 April, in which at least 26 people, most of whom were Indian tourists, were shot dead by gunmen at a beauty spot near the resort town of Pahalgam in the India-administered part of Kashmir.

In one of the worst attacks in recent times in Kashmir, which is split between the two countries, at least four gunmen fired at dozens of tourists in Baisaran meadow, which is three miles (5km) from Pahalgam, and known as “mini Switzerland”.

India described the massacre as a “terror attack” and said it had “cross-border” links, blaming Pakistan for backing it.

Pakistan denied any connection to the atrocity, which was claimed by a militant group called the Kashmir Resistance.

India’s defence ministry said its attack on 7 May – dubbed Operation Sindoor – was in response to that attack, hitting “terrorist infrastructure” in Pakistan and Pakistan-administered Kashmir “from where terrorist attacks against India have been planned and directed”.

Sky’s India reporter and producer Neville Lazarus said Sindoor is the vermilion, or bright red, colour a married woman wears in the middle parting of their hairline, indicating marital status.

He said the term being used for the military operation was significant because after the attack on the tourists near Pahalgam, there were many who were left widowed.

The terrorist groups India says it targeted

The Kashmir Resistance, also known as The Resistance Front, claimed responsibility for the 22 April attack.

The group, which emerged in 2019, is considered a splinter group of the Pakistan-based Lashkar-e-Taiba (LeT), according to the South Asia Terrorism Portal, a Delhi-based thinktank.

LeT is listed as a terrorist organisation by the UN. The same group was accused of killing 166 people during a four-day attack on Mumbai in 2008.

At the time, the group was alleged to have close ties to Pakistan’s spy agency, the Inter-Service Intelligence – an accusation Islamabad denied.

India said it hit camps in the 7 May strikes that were run by LeT and by Jaish-e-Mohammad (JeM), another UN-designated terrorist group said to be operating in the region.

Pakistan banned JeM in 2002 after it – along with LeT – was blamed for a 2001 attack on India’s parliament.

The group had links with al Qaeda and the Taliban, according to the UN Security Council.

JeM, which is believed to be based in Pakistan’s central city of Bahawalpur, has claimed responsibility for numerous suicide bombings in Kashmir.

India said it attacked Bahawalpur’s Markaz Subhan Allah, which it said is JeM’s headquarters, located about 100km from the border.

In a statement, JeM said its leader Masood Azhar lost 10 family members in the strikes.

Ajai Sahni, head of the South Asia Terrorism Portal, told Reuters that terrorist groups have been created by Pakistan as a way of creating a “pattern of denial that they were involved in terrorism in Jammu and Kashmir”.

Pakistan has always denied that it supports and funds militants in Kashmir, saying it offers only moral and diplomatic support.

Pakistan warns of further escalation

Pakistan has vowed to carry out its own form of retaliation for the latest strikes, with Prime Minister Shehbaz Sharif describing the strikes as an “act of war imposed by India”.

In a statement after India’s strikes, he said Pakistan “reserves the right to respond, in self-defence, at a time, place, and manner of its choosing to avenge the loss of innocent Pakistani lives and blatant violation of its sovereignty”.

He said the National Security Committee was convened and condemned India’s “unprovoked, cowardly and unlawful act of war”.

“These unprovoked and unjustified attacks deliberately targeted the civilian areas, on the false pretext of presence of imaginary terrorist camps, resulting in the martyrdom of innocent men, women, and children, and causing damage to the civilian infrastructure, including mosques,” it added.

Location of India’s strikes significant

The Indian government had been under “intense pressure” to act after the 22 April attack, says Sky’s military analyst Michael Clarke, adding a response had therefore been expected.

But he says the fact they hit several camps in other parts of Pakistan, beyond Pakistan-administered Kashmir, “is something of an escalation”.

He adds: “Now, the Indians are saying this is a very precise strike with missiles. And, in a way, they say this draws a line under it as far as the Indians are concerned.

“So they’re inviting the Pakistani side to do something purely symbolic and not to escalate,” Clarke adds.

“Pakistanis don’t look as if they’re in the mood to do that. They say that they will respond at a time and place of their choosing.”

Read more from Sky News:
Timeline: The story behind India and Pakistan’s deadly conflict
Decades of anger have turned into violence – the world should be worried

What’s behind the tension between the countries?

India and Pakistan have fought several wars and conflicts since their independence from Britain in 1947, primarily due to territorial disputes over Kashmir.

Both countries claim the region as their own, but in reality control different sections of the territory.

Armed insurgents in Kashmir have resisted New Delhi for decades, with many Muslim people in the region supporting the rebels’ goal of uniting the territory either under Pakistan’s rule or as an independent country.

The dispute over the land has claimed the lives of tens of thousands of people since 1947, although outbreaks of sporadic violence had appeared to have eased in recent years.

In 2019, a suicide bomber in a vehicle killed 40 paramilitary soldiers in a military convoy, which brought the two countries close to war.

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Before that, there was the Mumbai terror attack in 2008 and in 1999, the 10-week-long Kargil War.

That conflict began after Pakistan’s military covertly occupied Indian posts across the line of control (LoC) in the Kargil region.

At least 1,000 combatants were killed on both sides. The fighting stopped after Pakistan asked then US president Bill Clinton to help de-escalate the conflict.