The Hizbul Mujahedeen militant group has claimed responsibility for the Wednesday morning attack on an Indian paramilitary camp in Srinagar in Kashmir province.
Five Indian officers died at the police training camp, authorities said.
It was the first attack in the city of Srinagar in at least three years, CNN's sister network IBN reported.
A Hizbul Mujahedeen spokesman told a local news agency that two militants carried out "the guerrilla attack" and warned that "the outfit will carry on such attacks in (the) future also."
The attack comes a month after the execution in India of a Kashmir militant who led an attack on the nation's parliament in 2001. Nine people were killed in that incident.
Since Mohammed Afzal Guru's execution, his supporters in Srinagar have demanded through protest that his body be returned.
Authorities in India have accused Pakistan of backing Guru's attack, which led to a massive mobilization of troops by the two nuclear neighbors along their tense borders. Pakistan denied involvement.
Indian Home Secretary R.K. Singh -- who said three civilians and five police officers also were injured in the Srinagar attack -- said Wednesday he believes the attackers came from Pakistan. They "appeared ... to be not local, but from across the border," he said in New Delhi.
But Pakistan's Foreign Office dismissed India's charge.
"Pakistan strongly rejects any allegations made about its involvement in the incident in Kashmir on Wednesday," spokesman Moazzam Ahmed Khan said.
That stance was repeated in a Pakistani government press release, which added, "We feel that this trend of making irresponsible statements and knee-jerk reactions by senior Indian government functionaries have the potential of undermining the efforts made by both sides to normalize relation between the two countries."
Kashmir has been disputed territory between India and Pakistan since the two countries separated in 1947 after a costly war.
Militants supporting Pakistan have been fighting for more than 20 years against Indian rule in the parts controlled by that country, which has a mostly Muslim population.
The insurgency has killed more than 43,000 people, but some human rights groups and nongovernmental organizations put the death toll at twice that.
The two attackers in the Wednesday incident were killed, said Omar Abdullah, the chief minister of the Indian-administered Kashmir.
Journalist Mukhtar Ahmad reported from Srinagar and Ben Brumfield reported and wrote from Atlanta.
CNN's Harmeet Shah Singh contributed to this report.