A downed Indian fighter pilot who was attacked by a mob and then paraded on video by Pakistan's army has become the human face of a spiralling crisis between the nuclear-armed neighbours.

Key points: The furore emerged after Pakistan's military shot down two warplanes and captured the pilot on Wednesday

The furore emerged after Pakistan's military shot down two warplanes and captured the pilot on Wednesday The man's capture went viral online, with Indian supporters praising his courage

The man's capture went viral online, with Indian supporters praising his courage As tensions between the rivals escalate, India has begun building more than 14,000 bunkers

The furore emerged after Pakistan's military shot down two Indian warplanes and captured the pilot on Wednesday, raising tensions between the two rivals to a level unseen in decades.

The man was brutally beaten by Pakistani villagers and taken by soldiers in clips that have since gone viral on social media, seeing him fast emerge as a symbol of the dangerous flare-up between the arch-foes.

India has not confirmed the man's identity, but Indian media have given his name as Abhinandan Varthaman.

The airman's treatment at the hands of Pakistani troops drew both condemnation and praise, while at his house in southern India supporters gathered to record messages of solidarity.

In one video posted on social media, a Pakistani soldier ankle-deep in a stream of water in the disputed Kashmir region can be seen shielding the pilot from angry villagers and shouting "enough" as they pummel his bloodied face and strike blows against his limp body.

In another video, posted on Twitter by Pakistan's information ministry, the pilot is blindfolded and can be heard saying "I've got hurt and I would request some water".

He then reveals his name and rank before politely fending off questions from soldiers by saying: "I'm not supposed to tell you that."

Later, in a video released by Pakistan's military, the captured airman is shown without a blindfold, appearing more relaxed, thanking the Pakistani army and sipping tea.

"The officers of the Pakistani Army have looked after me well, they are thorough gentlemen," he said.

Sorry, this video has expired Indian Wing Commander comments on Pakistani army

Pakistan closes airspace, flights to Europe cancelled

India's foreign ministry branded Pakistan's videos as a "vulgar display" of an injured airman, saying they violated international humanitarian law and the Geneva convention.

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"Pakistan would be well advised to ensure that no harm comes to the Indian defence personnel in its custody," it said in a statement.

"India also expects his immediate and safe return."

Pakistan's army spokesman Asif Ghafoor tweeted a photo of the airman and said he was "being treated as per norms of military ethics". Pakistani tweeters said he had been shown exemplary hospitality.

Airlines operating flights out of East Asia to Europe have been forced to reroute planes.

Pakistan has closed its airspace entirely and Indian authorities restricted flights at more than half a dozen airports on Wednesday.

Flights via Pakistan have now been cancelled and other flights rerouted, while Thai Airways has suspended all flights to Europe.

"By closing the airspace, every flight from Thailand to Europe has been affected," Thai Airways president Sumeth Damrongchaitham told the BBC.

"For flights that are going to depart this evening, we will call an urgent meeting to consider the impact of such events."

The airline is yet to establish alternative routes for its flights.

Pakistan has closed its airspace entirely, forcing airlines to reroute planes around the country. ( Screenshot: Flight Radar )

India builds bunkers to protect families along border

As tensions between the nuclear-armed rivals escalate, India has begun building more than 14,000 bunkers for families living along its border with Pakistan in Jammu and Kashmir state.

It hopes the bunkers will keep them safe from artillery shells and avoid a mass evacuation of the area.

Some Pakistani families fled their homes after shelling along the Indian border. ( AP: M.D. Mughal )

On Tuesday evening, Pakistan used heavy calibre weapons to shell the Indian side of the de facto border known as the Line of Control (LoC) that divides the disputed Kashmir region, and the Indian army retaliated with its own shelling of the Pakistani side.

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This created "panic among people", said Rahul Yadav, the deputy commissioner of the Poonch district, a remote area of the Indian state that faced some of the attacks.

The new shelters, which were planned before this week's spike in tensions, are supposed to reduce that fear and prevent people from having to flee when the shelling begins.

There have been frequent exchanges of fire along the actual and de facto borders in recent months, but Tuesday's firing marked a major escalation after India carried out an air strike on what it said was a training camp run by an Islamist militant group in Pakistan.

India was responding to a suicide car bombing claimed by a member of the group that killed 40 Indian paramilitary police in Kashmir almost two weeks ago.

As well as the shelling, Pakistan retaliated on Wednesday by carrying out airstrikes on the Indian side of the border and, according to officials in Islamabad, shot down two Indian jets over Pakistan.

India accuses Pakistan of sponsoring militancy in Kashmir, Hindu-majority India's only Muslim-dominated region.

Kashmiri villagers gathered around the wreckage of an Indian aircraft after it crashed in Budgam area. ( AP: Mukhtar Khan )

ABC/wires