Pakistan has downgraded diplomatic ties with India and suspended trade with its neighbour as the political row over the disputed territory of Kashmir escalates.
India's announcement that it will abolish self-rule for Kashmir has been denounced as illegal in Islamabad, with the country's military warning it will "go to any extent" to support Kashmiris.
What options does Pakistan have?
Why is there pressure on Pakistan to act?
Kashmir has poisoned relations between India and Pakistan since Independence. Both claim the territory, which is now divided between them by a fortified line of control. They have fought three wars over it.
The dispute now symbolises the rivalry and mistrust between the neighbours and goes to the ideological heart of Pakistan. Pakistan's leaders have used protection of the Muslim majority residents of Kashmir as a unifying call for decades and championed Kashmiris' right to independence.
The unresolved conflict against a far larger neighbour has helped Pakistan foster a heavily militarised state. Moreover, much of Pakistan's water flows through the Himalayan territory, leaving Pakistani leaders concerned their supply could be held hostage. Delhi's sudden decision to revoke autonomy in Indian-administered Kashmir has therefore provoked widespread outcry, with accusations the government was blind-sided and has let Kashmiris down. "Even if the government wants to play it carefully, there's a lot of pressure from the public," said Umer Karim, a visiting fellow at the Royal United Services Institute.
What are the diplomatic options?
Pakistan's first move will be to try to occupy the moral high ground and deploy diplomatic resources, predicted Farzana Shaikh, a Pakistan expert at the Chatham House think tank. "We can expect Pakistan to try to mobilise international opinion and show that what India is doing is illegal and in clear breach of UN resolutions," she said. Imran Khan has said he will use all diplomatic channels "to expose the brutal Indian racist regime".
But realistically what could the United Nations do? Not much predicts Mr Karim. While forcing India to answer questions on its conduct at the United Nations could be embarrassing to Delhi, it will not change much on the ground, he said. Likewise Pakistan's first moves are largely symbolic.
Diplomatic ties have been downgraded during rows before and India has already withdrawn Pakistan's most-favoured-nation trading status to Pakistan and imposed customs duties of 200 per cent on Pakistani products.
What are Pakistan's military options?
Pakistan's military commanders have said they will go to "any extent" to support Kashmir, while the president of Pakistan-controlled Kashmir warned of war. Beyond the rhetoric, analysts believe military options are severely limited. Kashmir is already one of the most militarised regions in the world.
The neighbours face off against each other and regularly exchange artillery fire along the line of control. Both are also pointing nuclear weapons at each other. In such a stand-off any military action is fraught with the terrible risks of escalation.
Pakistan has for decades been accused of backing militants and insurgents who are fighting Indian forces in Kashmir. Anti-India jihadist groups have been allowed to live, recruit and fundraise freely in Pakistan, Delhi complains.
Pakistan's harbouring of militants has also overshadowed ties with the West, though Islamabad says it only provides moral support to Kashmiris.
Could Pakistan-based militants be about to unleash a new wave of attacks?
India's move in Kashmir comes as Pakistan's relations with America appeared to be suddenly warming. Imran Khan and army chief Gen Qamar Javed Bajwa were warmly welcomed in Washington by Donald Trump who is desperate for Pakistani help to extricate himself from Afghanistan.
American aid and trade beckon, but Washington still wants Islamabad to take "irreversible" steps against militant groups on its territory. Yet, with influential religious hardliners are now baying for militants to be unleashed to wage jihad in Kashmir, that puts Pakistan "in an impossibly difficult position, particularly the military establishment and Gen Bajwa," said Dr Shaikh.
"Clearly they want to repair relations with the US. What are they going to do about this call for irreversible action against militant groups at a time when everyone across the political spectrum is baying for blood?"