Indian forces have killed three Pakistanis involved in the April attack on Hindu tourists in the Jammu and Kashmir federal territory in which 26 men were shot dead, Home Minister Amit Shah said on Tuesday.

The attackers, who New Delhi said were Pakistani nationals backed by Islamabad, had opened fire in a valley popular with tourists in Kashmir's scenic, mountainous region of Pahalgam, before fleeing into the surrounding pine forests.

The attack led New Delhi to target what it called "terrorist infrastructure" in Pakistan and Pakistani Kashmir, leading to four days of intense fighting between the nuclear-armed neighbours before they agreed to a ceasefire.

"I want to tell ... the entire nation that these were the three terrorists who killed our citizens ... and now all three have been killed," Shah told parliament during a discussion on the India-Pakistan conflict.

The three were killed in an intense gun battle in a Kashmir forest on Monday, the Indian army said.

Pakistan has denied involvement in the attack - the worst assault on civilians in India since the 2008 Mumbai attacks - and sought an independent investigation.

Shah said that India had a "lot of proof" that the dead "terrorists" were Pakistanis as security forces had recovered Pakistani voter identity cards of two of them and chocolates made in Pakistan.

Forensic tests showed that the rifles they had with them were used in the April attack, he added.

Pakistan's foreign ministry did not immediately respond to a request for comment on Shah's remarks.

The Himalayan region of Kashmir is at the heart of the hostility between India and Pakistan, who have fought two of their three wars over the region, which they both claim in full but rule in part.

New Delhi accuses Islamabad of helping Islamist separatists battling security forces in its part of Kashmir, but Pakistan says it only provides diplomatic and moral support to Kashmiris seeking self-determination.