The Indian army's chief of staff ordered an "aggressive" response Monday to any cross-border firing by Pakistan as commanders from both sides met to discuss a recent deadly flare-up in disputed Kashmir.

"We expect our commanders to be aggressive," General Bikram Singh said ahead of the brigade-level talks along the de facto border in Kashmir known as the Line of Control (Loc).

"The orders are very clear: when provoked, I expect my unit commanders should fire back," Singh added.

India says one of its soldiers was beheaded and another was killed by the Pakistani army on January 8, an incident that has rocked an already fragile peace process between the two sides.

Pakistan denies its troops were to blame for any such incident and says that two of its own soldiers were killed in the last eight days along the LoC, where a ceasefire has been in place since 2003.

Singh said the treatment of the Indian soldiers was "an unpardonable act".

"We want the Pakistani army to hand over the head of the soldier as soon as possible," he said at a press conference in New Delhi.

"We want to keep the dialogue process on and also explore the best ways to communicate with Pakistan, but the attacks must stop," Singh added.

The general said the attack which led to the beheading must have been planned for up to a fortnight and reiterated the claim that it was the work of the Pakistan army.

"These kind of operations require planning of at least 10-15 days. You have to observe the activities, arrange the logistics, firepower. You have to have a plan and practise that plan. No one would like to leave tell-tale signs," he said.

"The clockwork precision, detailed planning and execution... is indicative of premeditated and pre-planned action of Pakistan."

The family of the decapitated soldier, Lance Naik Hemraj, has gone on a hunger strike as part of a campaign to ensure that his severed head is returned.

"I want my husband's complete body. He served the country and deserves respect," his wife Dharmvati told the Hindi-language Zee TV news channel.

Kashmir, a Muslim-majority territory, is divided into Indian and Pakistani-administered sectors but is claimed in full by both sides.

It has been the cause of two of three wars between India and Pakistan since independence from Britain in 1947.