Jaish-e-Mohammed is responsible for the fidayeen (guerilla) attack on an army brigade headquarters in Uri, Kashmir, the Indian Army has said.
Director General of Military Operations (DGMO) Lt. Gen Ranbir Singh said the weapons recovered from the slain terrorists had Pakistan marking.
"Four AK 47s, four Under Barrel Grenade Launchers and other war like stores were recovered from the four terrorists who were killed. All the weapons had Pakistan marking,” Singh said in a press statement.
The Army's statement means this will be JeM's second deadly attack on Indian forces in the last nine months. Indian intelligence agencies believed the group also had a hand in the attack on Pathankot Air Force Station on January 2, which had resulted in deaths of six soldiers.
Jaish-e-Mohammed (JeM) is a Kashmir-based Islamist militant group. The group is viewed by the Indian intelligence agencies as the principal terrorist organisation in Jammu and Kashmir.
The group, helmed by Maulana Masood Azhar, has been deemed as a terror outfit by India and United States.
Meanwhile, Indian Prime Minister Narendra Modi condemned the attack on the army brigade headquarters in Uri.
He also promised to punish the perpetrators for the "despicable" and "cowardly" attack on the army base.
Seventeen Indian soldiers were killed after four suicide gunmen attacked the army's battalion headquarters in Uri. The armed men were later neutralised, Indian authorities said.
India's defence ministry said a total of 35 soldiers had been wounded in the attack which began at 4 am local time.
"We strongly condemn the cowardly terror attack in Uri. I assure the nation that those behind this despicable attack will not go unpunished," Modi said in a tweet following the raid.
We strongly condemn the cowardly terror attack in Uri. I assure the nation that those behind this despicable attack will not go unpunished.
India's interior minister Rajnath Singh has accused Pakistan of orchestrating the attack. "Pakistan is a terrorist state and it should be identified and isolated as such," the senior minister said, PTI reported.
He also said the militants were "highly trained" and "heavily armed".
There are definite and conclusive indications that the perpetrators of Uri attack were highly trained, heavily armed and specially equipped.
India's defence minister Manohar Parrikar will travel to Kashmir to probe the attacks, the deadliest since 2014 which also took place in Uri.
India's army chief General Dalbir Singh Suhag rushed to Kashmir in the wake of the attack.
A senior home ministry official said the attack was "clearly a case of cross-border terror attack".
According to reports by Indian media, an alert was generated on September 15 by the Intelligence Bureau about a possible Fidayeen attack in Uri sector.
The alert was sent to everyone in the "crisis loop" including all the Army command units in the state, media reports said.
Pakistan has reacted strongly to India's claims. "India immediately puts the blame on Pakistan without doing any investigation. We reject this," Reuters quoted foreign ministry spokesman Nafees Zakaria as saying.
Meanwhile, Pakistan military's media wing issued a statement saying that Pakistan and Indian army's DGMO have established a hotline on India's request.
The media wing refuted India's suggestion of the Uri attack being orchestrated from across the border. "No infiltration is allowed from Pakistani soil because water tight arrangements are in place," it said.
Pakistan's DGMO has asked his Indian counterpart to "share any actionable intelligence", Pakistan military further said.
In 2001, JeM terrorists had stormed in India's Parliament in New Delhi, killing 5 security personnel.
Watch: Major JeM attacks in India since 2000
Timeline of Uri attack
5:30 am: Four heavily armed men sneak into the army camp in Uri town before dawn and target soldiers
8:00 am: The Army sends three choppers from Indian Army’s 19 divisional headquarters in Baramulla to Uri
8:10 am: Interior Minister Rajnath Singh postpones visit to Russia and the US
8:50 am: Rajnath Singh calls for an emergency meeting of concerned officials over the ongoing encounter in Uri
9:00 am: Rajnath Singh speaks to the governor and chief minister of Jammu and Kashmir
9:57 am: High-level security meet to take place at Rajnath Singh’s residence at 12:15pm. Senior home ministry and defence ministry officials to attend the meet
10:15 am: All four terrorists gunned down by the Army. Search operation under way
10:59 am: Army Chief General Dalbir Singh to visit Kashmir in the wake of the terror attack
11:00 am: 17 soldiers killed in Uri terror attack: Indian Army
11:01 am: Indian Defence Minister Parrikar to visit Srinagar
11:36 am: Congress vice-president Rahul Gandhi condemns Uri attack
11.54 am: Ministry of home affairs issues alert for all airports across the country
12:04 pm: Interior Minister Rajnath Singh briefs Prime Minister Narendra Modi on Uri
12:48 pm: Congress President Sonia Gandhi expresses shock and deep distress over the martyrdom of Indian soldiers