Four Pakistan Army soldiers were martyred by shelling across the Line of Control in Azad Jammu and Kashmir's Jandrot sector on Monday, according to a statement issued by Inter-Services Public Relations (ISPR).
The army's media wing said that the troops were busy with maintenance of a communication line when they were "fired upon and hit by [a] heavy mortar round."
The ISPR said three Indian soldiers were killed and a "few injured" in an exchange of fire.
The latest incident of cross-border firing comes days after Indian Army Chief Gen Bipin Rawat threatened to call Pakistan's "nuclear bluff" in a statement regarded as reckless and irresponsible by Pakistani leadership.
Islamabad summons New Delhi's envoy
Later in the day, the Foreign Office summoned Indian Deputy High Commissioner J.P. Singh to lodge a protest about the incident, the state-run Radio Pakistan, reported.
FO Spokesperson Dr Mohammad Faisal said ceasefire violations by India are a "threat to regional peace" and security, and may lead to a strategic miscalculation.
"India continues to indulge in ceasefire violations despite calls for restraint," Faisal was quoted as saying.
Deliberately targeting civilian populated areas and troops carrying out maintenance activities is indeed deplorable and contrary to human dignity, international human rights, and humanitarian laws, the Foreign Office maintained.
Furthermore, Islamabad urged the Indian side to respect the 2003 ceasefire arrangement, investigate the latest violation and other such incidents, and maintain peace on the LoC and the Working Boundary.
According to the Foreign Office, Indian forces have committed more than 70 ceasefire violations along the LoC and Working Boundary in 2018, in which at least one civilian has died and five people have been injured.
Ceasefire violations are a frequent feature along the LoC and Working Boundary despite the leadership of Pakistan Rangers and India's Border Security Forces agreeing in November 2017 that the "spirit" of the 2003 Ceasefire Agreement must be revived to protect innocent lives.
Unprovoked firing by Indian forces across the LoC had taken 832 lives, left 3,000 injured and had damaged 3,300 houses in the first half of 2017, according to the director general of the Disaster Management Authority, Zaheeruddin Qureshi.