India's ministry of defense Lieutenant Colonel Rajesh Kalia said he had no knowledge of the incident.
India and Pakistan have been in confrontation for decades across the LoC. The old ceasefire line runs through a region that both countries claim in full but rule in part.
Growing exchanges of fire in past months have frayed a 2003 truce.
One body has been recovered from the Neelum River and a search is underway for the remaining three, the military said.
In November a civilian bus was hit by Indian firing in the same region, killing 12 people.
Pakistan's military said it had responded to the ceasefire violation by firing at Indian soldiers.
In May India accused Pakistani forces of killing two soldiers patrolling the LoC and mutilating their bodies.
Pakistan's military denied the allegations and said it had not committed ceasefire violations.
Both sides have previously accused each of violating the ceasefire and of beheading soldiers in the past.