A Pakistani soldier has been killed by Indian troops in the divided Kashmir region, according to the Pakistani military.
Thursday's incident comes two days after the Indian army said that two Indian soldiers were killed by Pakistani troops who crossed the ceasefire line in the Himalayan region.
Pakistan has denied such an incident occurred.
A Pakistani army spokesperson said that the soldier was killed by "unprovoked" Indian fire while manning a post in the Battal sector of Kashmir, which is split between the two sides by a heavily fortified border known as the Line of Control (LOC).
"Pakistan Army soldier, Havildar Mohyuddin, embraced shahadat [martyrdom] due to unprovoked firing by Indian troops at Hotspring sector in Battal at 2:40 pm (0940 GMT) today," the military said.
In a major diplomatic move on Wednesday, Pakistan's high commissioner was summoned to New Delhi to discuss Tuesday's incident, as the country lodged a protest with Pakistan after the incident at the LOC.
The Pakistani military has said that its investigations had revealed no evidence of the deaths of the two Indian soldiers.
Al Jazeera’s Kamal Hyder, reporting from Islamabad, said: “The Pakistani media and government are quite concerned that there is a war hysteria being whipped up by the Indian military. The Indians have rejected Pakistani claims that there should be an Independent enquiry into the recent deaths of the two Indian soldiers by the UN.
“There are also contradictory reports coming from the Indian military’s northern command which maintains that there was no alleged mutilation of the Indian soldier, as was reported in the Indian media.”
The alleged retaliatory attacks threaten to reverse the recent progress Pakistan and India have made in improving their historically antagonistic relationship.
The escalations on the Line of Control will be a source of worry for both sides in light of the ceasefire that has held since 2003.
The two countries have fought three major wars since they achieved independence from British India in 1947, two of them over Kashmir.
Their relationship reached a recent low point in 2008 when Pakistani men killed 166 people in the Indian city of Mumbai. It has improved significantly since then, and the two countries have taken steps to improve cross-border trade and ease travel restrictions. But key issues, including Kashmir, remain unresolved.
Al Jazeera’s Divya Gopalan, reporting from New Delhi, said: "The lines Indian media are putting out are that ‘Pakistan alleges that a Pakistani soldier was killed by Indian troops’.
"Very little is being said about this new incident. The focus is still on what happened two days ago when two Indian soldiers were shot by Pakistani troops. TV stations are playing out how many Pakistani violations there have been in the past year.
"After going through a period of thawing relations where both countries were extending hands of friendship to each other. People are now concerned, especially on a political level, about how that is going to affect relations especially after this new shooting.
"The Indian home minster has made no mention of backtracking on any of the diplomatic progress made between the two countries.
"The neighbouring countries have been going through a period of thawed relations extending hands of friendship to each other - but all that could change especially since the renewed rhetoric is ratcheting up."