India has conveyed its "deepest concern and protest" to Pakistan's high commissioner in New Delhi over the alleged killing of two Indian soldiers along the countries' defactor border in Kashmir, India's foreign minister says.
Indian army officials say the two Indian soldiers were killed after Pakistani troops crossed the ceasefire line in the Himalayan region and attacked an army patrol on Tuesday.
The Pakistani military has denied that the soldiers were killed, saying that its investigations had revealed no evidence the incident had occurred.
Al Jazeera's Divya Gopalan, reporting from New Delhi, said that Salman Bashir, Pakistan's envoy, had arrived on Wednesday morning to discuss the incident.
"This is a major diplomatic move, because it is very rare for the Pakistani high commissioner to be summoned like this," said Gopalan.
Salman Khurshid, India's foreign minister, said on Wednesday, following the meeting, that Bashir had been "spoken to in very strong terms".
He said that the alleged violation of the Line of Control (LoC), the defacto border that separates the Pakistani- and Indian-administered parts of Kashmir, was "a matter of great concern and if it is not immediately contained it will have an adverse impact [on the peace process]".
"This [attack] has been conveyed as being unacceptable we are doing the best that is possible and I expect there will be some response from the other side," he said.
He added that hostilities "must not be escalated".
Military officers in contact
"The Director-Generals of military operations of both sides have been speaking via hotline since the incident and they are also due to meet," reported Al Jazeera's Gopalan.
She added that military experts are saying that the incident should be treated as a crime, and not an act of war.
The incident was "a significant escalation ... of ceasefire violations and infiltration attempts supported by the Pakistan
Army," said Rajesh K Kalia, spokesman for the Indian army's Northern Command.
Earlier, Foreign Minister Khurshid said India would deliver a "proportionate response" to the "ghastly" killings in Kashmir which he said were designed to sabotage an already fragile peace process.
In Islamabad, the Pakistan military denied what it called an "Indian allegation of unprovoked firing".
"This is Indian propaganda to divert attention from an Indian raid on Sunday on a Pakistani post in which a Pakistani soldier was killed," it said in a statement. On Wednesday, Pakistan's foreign office said the allegation was "baseless", saying that Pakistan was prepared for an investigation to be carried out through the United Nations Military Observers Group for India and Pakistan (UNMOGIP).
Kalia said the incident happened in the Mendhar sector of Indian-administered Kashmir.
"Pakistan army troops, having taken advantage of thick fog and mist in the forested area, were moving towards own posts when an alert area domination patrol spotted and engaged the intruders," Kalia said in a statement.
"The fire fight between Pakistan and own troops continued for approximately half an hour after which the intruders retreated back towards their side of Line of Control."
He said the body of one of the slain soldiers was found "badly mutilated". On Wednesday, J Dahiya, India's chief military spokesperson, said that one of the soldiers had been "beheaded", adding that the Indian military was "absolutely convinced" that the Pakistani army was responsible.
Both sides have said that there have been increased skirmishes and increased violations over the past few weeks at the border.
Al Jazeera's Kamal Hyder, reporting from Islamabad, said neither side would want to escalate the situation along the border.
"It's quite possible that its Kashmiri fighters who may have engaged, who may have been trying to infiltrate along this long, mountainous border. It happens from time to time," he said.
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The deaths came after Pakistan said on Sunday that one of its soldiers was killed by Indian shooting, with each side blaming the other for the flare-up.
Firing and small skirmishes between the two countries are common along the LoC that divides the contested Himalayan region of Kashmir between India and Pakistan, despite slowly improving ties in recent years.
The Indian army says eight of its soldiers were killed in 2012, in 75 incidents.
In recent efforts to improve relations, trade and more lenient visa rules have been a feature of talks between senior political leaders from both sides.
Al Jazeera's Gopalan said that despite signs of improving relations, the Indian government remained cautious.
She said it was not clear what action India would take in response to the killing of the soldiers.
"According to the army, it's going through official channels at the moment," she said. "Many are saying that any type of retaliatory action would be hugely unadvised."
India and Pakistan both claim Kashmir in full. It was the cause of two of three wars between the neighbours since independence from Britain in 1947.