Three Indian soldiers were killed on the de-facto border between India and Pakistan in the heavily disputed region of Kashmir Tuesday, according to army officials.
The Indian army called the attack "cowardly" and threatened "retribution" in a tweet. Multiple army sources, who spoke on the condition of anonymity, said the attackers crossed the border from the Pakistani side to launch the attack.
Heavy cross-border firing and shelling followed the attack at several posts in Machil sector.
There was no immediate comment from Pakistan, which reported that four of its soldiers were killed in a cross-border attack the day before.
Clashes between the rival nuclear-armed nations in the divided Kashmir region have become routine in recent weeks, causing civilian and army casualties on both sides.
Islamabad and New Delhi blame each other for firing the first shot in violation of a 2003 cease-fire deal in the Himalayan region.
Military tensions have raised fears of a wider conflict between them as a bilateral peace dialogue remains suspended.
