Jammu/New Delhi, Jan 8 (IANS): In a brazen violation of the 2003 ceasefire, Pakistani troops Tuesday intruded into Jammu and Kashmir and killed two Indian soldiers by slitting their throats, officials said. They also opened heavy fire on Indian posts on the LOC late Tuesday.

India condemned the killings as "absolutely unacceptable" and "inhuman" and said it will give a "proportionate response", while the Pakistan Army dismissed the "allegations".

Pakistani soldiers, apparently from the 29 Baloch Regiment, took advantage of a dense fog to sneak into an Indian post in Sona Gali area in the border district of Poonch.

Poonch Deputy Commissioner A.K. Sahu said the Pakistanis killed two Indian soldiers and wounded a third. "(The) Pakistani soldiers ... slit the throats of two army soldiers."

A defence ministry spokesman said the incident took place at 11.30 a.m. "Pakistani soldiers killed two Indian soldiers, and mutilated the body of one.

"We strongly condemn the brutality with which the body was treated," the official told IANS.

There was a fresh violation of the ceasefire late Tuesday as Pakistani troops opened heavy fire on Indian posts in Krishnaghati sector of Poonch around 7 p.m. Indian troops retaliated and the gunfight was on till 11.30 p.m. There was no report of any casualty on either side.

External Affairs Minister Salman Khurshid said that the government will make it clear to Pakistan that the action of its troops was absolutely unacceptable and it needed answers.

"It is not something of light nature, public opinion does not accept it," Khurshid told NDTV news channel.

Terming the incident an unwholesome development, he said India will factor it in the roadmap for the future.

"We want proportionate response... (will take) a collective view in the government," he said, adding it seemed a ploy to derail peace talks.

India also termed the Pakistani action "provocative".

"The Government of India considers the incident as a provocative action and we condemn it. Directors General of Military Operations (DGMOs) of the two countries are in touch over it,the defence ministry said in a statement, adding the matter will be taken up with Pakistan.

Political parties in India also strongly condemned the ceasefire violation and the killing of two Indian soldiers, saying the incident will have an impact on bilateral ties.

The Bharatiya Janata Party (BJP) said that talks with Pakistan should be called off while Congress said that Pakistan owes an explanation.

Northern Army Command chief Lt. Gen. K.T. Parnaik, who later visited the spot, asked the army to "stay alert and calm" and declared that "appropriate action will be taken at the appropriate time".

Army sources told IANS that the Pakistani troops took away the weapons of the dead Indians: Sudhakar Singh and Hemraj of 13 Rajputana Rifles.

There were reports that one of the Indian soldiers was decapitated and the Pakistanis took away the head, but it could not be independently confirmed.

The sources said the Pakistanis reached the post since it was located close to the fence near the LoC, which divides Kashmir between India and Pakistan.

The Indian Army has erected a three-tier fence in Indian territory running along the LOC. The fence is about 500 metres to two kilometres inside Indian territory and seeks to prevent Pakistani intrusion.

But the Pakistanis sneaked in using the fog in the forested area as a cover, an army spokesman said.

"The (Indian) patrol spotted them and engaged the intruders" for about half hour after which the Pakistani troops retreated, he said.

The report of the Pakistani attack came soon after India told Pakistan "to ensure that the sanctity of LoC is upheld at all times".

In response, Pakistan Army "rejected allegations of the Indian army about the unprovoked firing by Pakistani troops at the Line of Control", reported Radio Pakistan.

Also Tuesday, Pakistani army chief General Ashfaq Parvez Kayani visited Sialkot and asked the army to remain "fully prepared to respond to the full spectrum of threats, direct or indirect, overt or covert".

The Indian external affairs ministry denied that Indian troops crossed the LoC in Rampur sector or violated the ceasefire in force since 2003 in the area as claimed by Islamabad.

"India is committed to the sanctity of LoC," a ministry spokesman said, calling it the most important part of the India-Pakistan confidence-building measures.

"We call upon the Pakistan authorities to ensure that the sanctity of the LoC is upheld at all times."

The spokesman was referring to an earlier incident which Pakistan says involved firing by Indian troops that left one of their soldiers dead.

India says it were the Pakistani who triggered the earlier gun battle.

Their "unprovoked firing on Indian troops" damaged the roof of a house in Churunda village. "Indian troops undertook controlled retaliation in response."

Jammu and Kashmir Chief Minister Omar Abdullah termed the violation of the ceasefire "bad enough" and the mutilation as "unacceptable".

"Violation of the cease fire is bad enough, to resort to mutilating soldiers is unacceptable in any civilised society," he tweeted, adding it seemed an attempt to derail dialogue.