Outraged by the brutal killing of two of its soldiers by intruding Pakistani troops, India today strongly protested to Pakistan, warning that the "unacceptable" incident will have adverse impact on the ties.

As strong reactions by the government and political parties came, Pakistan High Commissioner Salman Bashir was summoned by Foreign Secretary Ranjan Mathai, who conveyed India's "deepest concern and protest" over yesterday's attack in which two Indian soldiers were killed and their bodies subjected to "barbaric and inhuman mutilation".

Pakistan was also asked to immediately investigate these actions that are in contravention of all norms of international conduct and ensure that these do not recur.

External Affairs Minister Salman Khurshid said the Pakistan envoy was "spoken to in very strong terms" and the deepest concern and protest over the incident was conveyed. He called the incident "completely unacceptable".

India's Director General of Military Operations (DGMO) Lt Gen Vinod Bhatia spoke to his Pakistani counterpart Maj Gen Ashfaq Nadeem to complain about the attack. A Pakistani military official said in Islamabad that Gen Nadeem rejected Indian army's contention of cross-Line of Control(LoC) firing by Pakistani troops and killing of any Indian soldier.

Referring to last month's Indo-Pak discussions on conventional CBMs, wherein maintaining the sanctity of the LoC, one of the most important CBMs between the two countries, was emphasised, Khurshid said,"therefore violation of (ceasefire) that itself is something which is a matter of great concern. And that would obviously, if not immediately, contained will have adverse impact on what we have been trying to do for such a long time."

Reacting sharply to the incident, Defence Minister A K Antony said "Pakistan Army's action is highly provocative. The way they treated the dead bodies of Indian soldiers is inhuman....We are closely following the situation."

In a gruesome attack, Pakistan regular soldiers crossed into Indian territory in Poonch sector of Jammu and Kashmir yesterday and ambushed an Indian patrol killing two soldiers, one of whom was decapitated.

Khurshid also stressed the need "to make sure that whatever happened should not be escalated. We cannot and must not allow escalation of this very unwholesome event that has taken place." 

Khurshid also said, "the manner in which the bodies have been treated, of course, the manner is of very very deep concern.

"This has been conveyed as unacceptable. We are doing the best that is possible and I expect there would be some response from the other side. Our intent is being conveyed very clearly. Our anxiety has been conveyed very clearly. Now we would expect an appropriate response from other side. I think, once again we feel this is completely unacceptable."

Reacting strongly, Congress said, "What Pakistan has done on our borders is unfortunate. Pakistan should not try our patience. We have lost our patience now."

Alleging that the neighbouring country does not have respect for Line of Control, Congress spokesperson Rashid Alvi said, "We want good relations with all neighbouring countries including Pakistan. But Pakistan itself has put a question mark."

Condemning the brutal killing, BJP said it was a "warning" to India and asked the government to place all facts before the international community so that Islamabad can be "named and shamed" before the world at large.

BJP leader Arun Jaitley also asked the government to "clearly define the dos and don'ts" in relations with the neighbouring nation.

"Pakistan must respect rules of engagement and the ceasefire agreement. How can we tolerate mutilation of our braves. Redlines must be drawn," Information and Broadcasting Minister Manish Tewari said in his tweets on the social networking site Twitter.

Meanwhile, Pakistan High Commission today issued a statement denying involvement of its troops in the attack and said it was prepared to hold investigations through the UN Military Observer Group on the recent ceasefire violations on the Line of Control.

The Pakistan High Commission statement came shortly after India summoned its High Commissioner Salman Bashir here to lodge a strong protest on the brutal killing of two of its soldiers by intruding Pakistani troops.

Pakistan "strongly rejects the Indian allegation of an attack across the LoC on its military patrol in which two Indian soldiers were claimed to have been killed. These are baseless and unfounded allegations," the statement said.

"Pakistan is prepared to hold investigations through the United Nations Military Observer Group for India and Pakistan (UNMOGIP) on the recent ceasefire violations on the Line of Control," the statement said.

Asserting that it was committed to a constructive, sustained and result-oriented process of engagement with India, Pakistan said, "We have made significant progress in the dialogue process.

"Pakistan has taken a number of steps to normalise and improve bilateral relations. It is important that both sides make serious efforts in maintaining this improvement and avoid negative propaganda."