Militants have attacked an Indian army brigade headquarters near the de facto border with Pakistan, killing 17 soldiers in one of the most deadly attacks in the northern region of Kashmir in a quarter-century-old insurgency.
Four "fidayeen" - or commando-style gunmen willing to fight to the death - were confirmed killed after penetrating the base in Uri near the Line of Control with Pakistan, an Indian army spokesman said.
Indian Prime Minister Narendra Modi strongly condemned what he called the "cowardly terror attack".
"I assure the nation that those behind this despicable attack will not go unpunished," Modi said in a series of Twitter posts.
Television reporters at the scene said the dawn raid had surprised soldiers in their sleep. The attackers set fire to a building before the four were killed in a gunfight that lasted several hours.
An army spokesman confirmed that the number of soldiers killed in the attack had risen to 17, making the toll far worse than a similar raid on an army base in Punjab state in January that India blamed on Pakistan-based militants.
Television footage showed helicopters flying to evacuate the injured as an operation continued to secure the area. Smoke rose from the compound, set in mountainous terrain. The Defence Ministry put the number of wounded at 35.
The raid comes amid heightened tension in India's only Muslim-majority region, which has faced more than two months of protests following the July 8 killing of a popular separatist commander.
At least 78 civilians have been killed and thousands injured in street clashes with the Indian security forces, who have been criticised by human rights groups for using excessive force including shotguns that fire pellets that have blinded people.
Indian-ruled Kashmir is one of the world's most militarised regions, with hundreds of thousands of soldiers, paramilitaries and police deployed to guard the frontier with Pakistan and contain a restive people with strong leanings towards greater autonomy and even independence.
"It is clearly a case of cross-border terror attack. We don't know which militant group is involved," a senior Home Ministry official told Reuters.
Pakistan rejected allegations that it was involved. "India immediately puts blame on Pakistan without doing any investigation. We reject this," foreign ministry spokesman Nafees Zakaria told Reuters.
There has been no claim of responsibility.
