India's prime minister on Monday summoned top security advisers to thrash out a response to a deadly raid on a Kashmir army base blamed on militants from Pakistan, amid calls for tough action against the nuclear-armed nation.

Narendra Modi has vowed to punish those behind the attack in which gunmen hurling grenades stormed a base, killing 17 soldiers in the worst such attack in over a decade. An 18th soldier died in hospital on Monday.

The Hindu nationalist prime minister promised during his election campaign to take a hard line over Kashmir and has faced calls from army veterans -- and even some in his own party -- for military action against Pakistan.

On Monday he summoned his national security adviser and military leaders to formulate a response, which media reports said could include air strikes on training camps on the Pakistan side of the Line of Control (LoC) that divides Kashmir.

But security experts say India lacks the military capabilities to take on its neighbour in the divided Himalayan region, already tense after weeks of violent clashes between police and demonstrators protesting at Indian rule.

"It's not like the US conducting air strikes in Syria to tackle ISIS that's hundreds of miles away from home ground, Pakistan is next door," said Ajai Sahni, executive director at the Institute of Conflict Management think-tank in Delhi.

"India knows it can't sustain a 15-day war against Pakistan and Pakistan knows it can't sustain a similar war against India."

Local media also urged caution, with the Indian Express saying calls for military action were "easier made than acted upon".

- 'Right to respond' -

Kashmir is divided between India and Pakistan but both claim it in full. The two nuclear-armed neighbours have fought three wars since gaining independence from British rule in 1947, two of them over Kashmir.

India regularly accuses its arch-rival of arming and sending rebels across the heavily militarised border that divides Kashmir between the two countries, to launch attacks on its forces.

Ranbir Singh, the army's director-general of military operations, said the markings on some of the material recovered from the slain militants showed they had come from across the border, while insisting India had the resources to adequately respond to Pakistan.

"The Indian Army has displayed considerable restraint while handling the terrorist situation both along the Line of Control and in the hinterland," he said at a media briefing Monday.

"...We reserve the right to respond to any act of the adversary at a time and place of our own choosing."

On Sunday Home Minister Rajnath Singh accused Pakistan of "continued and direct support to terrorism and terrorist groups" and called for it to be internationally isolated.

As the war of words intensified on Monday, Pakistan's army chief Raheel Sharif said his forces were "fully prepared to respond to entire spectrum of direct and indirect threat".

Islamabad meanwhile accused New Delhi of trying to deflect attention from weeks of unrest in Indian-administered Kashmir with what it called "vitriolic and unsubstantiated statements".

"It is a blatant attempt on India's part to deflect attention from the fast deteriorating humanitarian and human rights situation in the Indian-occupied Kashmir since the death of Burhan Wani," Pakistan's foreign ministry said in a statement.

- Wreath-laying -

Sunday's attack followed weeks of protests sparked by the killing of the popular rebel leader in a gunfight with security forces.

At least 87 civilians have been killed and thousands injured in clashes between protesters and security forces, the worst unrest to hit Kashmir since 2010.

On Monday more than 50 people were injured when security forces fired tear gas and pellet guns at protesters who defied a curfew in southern Kashmir, according to local police.

Sunday's attack was one of the bloodiest on soldiers since an armed rebellion against Indian rule erupted in 1989. Militants killed 30 soldiers and their families in a suicide attack in Kaluchak area in 2002.

On Monday soldiers paid tribute to their colleagues, most of whom died when their tents and other accommodation caught fire, at a wreath-laying ceremony in Kashmir's main city of Srinagar.

The Indian army has blamed Pakistan-based militant group Jaish-e-Mohammad, which was implicated in an audacious attack on an Indian air force base in Pathankot in the northern state of Punjab in January that left seven soldiers dead.

That attack dashed hopes of a revival of peace talks, which have been on ice ever since.

Rebel groups which have been fighting Indian troops in Kashmir since 1989 seek either independence for the region or its merger with Pakistan.

Soldiers have been deployed in the territory for decades and currently number around 500,000. Tens of thousands of people, mostly civilians, have died in the fighting.

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