NEW DELHI: India stepped up patrols along its de facto border with Pakistan on Monday after gunmen killed 17 soldiers at a nearby army base, as Prime Minister Narendra Modi's administration weighed its response to an attack India blames on its neighbour.

The assault, in which four commando-style gunmen burst into the brigade headquarters in Uri at 5.30 a.m. (midnight GMT) on Sunday, was among the deadliest in Kashmir and has sharply ratcheted up tension between the nuclear-armed arch-rivals.

Indian Home Minister Rajnath Singh on Sunday called Pakistan "a terrorist state" and Lieutenant General Ranbir Singh said troops were "ready to give a befitting response", without elaborating. Pakistan denies any role and accused India of apportioning blame before it had properly investigated.

Kashmir, divided between India and Pakistan since 1947, is at the heart of the rivalry between the neighbours. Two of their three wars since independence from Britain have been fought over the region.

Indian troops searched three ravines that cut across the border in mountainous terrain near Uri, which a senior army official said they believe the militants sneaked across.

Reinforcements were also sent to patrol one of the world's most heavily militaries frontiers, where Indian and Pakistani forces in places stand eyeball to eyeball and sometimes exchange fire, the army official said.

Modi is expected to meet senior leaders from his party at a cabinet meeting in New Delhi at noon on Monday, where politicians are set to discuss how to respond as well as the security lapses.

"Our first priority is to fortify every defence base and it is shocking that one of our strategic locations was hit," a senior aide to Modi told Reuters. "It has exposed the flaws and the weakness of our security infrastructure and an immediate overhaul is the first job on hand."

As well as the 17 confirmed dead, army officials said three of the critically wounded had been flown to an army hospital in New Delhi. Most of dead and wounded suffered severe burns after their army tents and temporary shelters caught fire from incendiary ammunition while they were sleeping.

The assault came as India's portion of Kashmir has been under a major security lockdown during more than two months of protests sparked by the July 8 killing of a commander of another Pakistan-based separatist group.

India has long blamed Pakistan for a role in the 27-year long insurgency against its rule in its only Muslim-majority state.

India's General Ranbir Singh said Sunday's assault bore the hallmarks of Pakistan-based militant group Jaish-e-Mohammed.

Pakistan denies sending fighters into Indian-administered Kashmir.

"Pakistan categorically rejects the baseless and irresponsible accusations being levelled by senior officials in Prime Minister Modi's government," the foreign affairs adviser to Pakistan's prime minister said in a statement late on Sunday.

Recent unrest in Kashmir has been led largely by local young men angry at the heavy military presence in the region.

Eighty-two civilians have been killed and more than 7,000 wounded as a daily curfew paralyses life. Two policemen have also been killed in clashes.

Pakistan has called on the United Nations and the international community to investigate atrocities it alleges have been committed by Indian security forces in Kashmir.

The UN is preparing to hold its annual general assembly in New York, where Kashmir is likely to be on the agenda.