Foreign Office spokesman Aizaz Ahmad Chaudhry expressed concern at the "brutal" attack on Ranjay. "We have conveyed our concern to the Indian government in this regard and demanded that an investigation into the incident be held and perpetrators of this heinous crime be brought to justice," he said in a statement.
Ranjay, a resident of Sialkot in Punjab province, was serving a life term after being convicted of involvement in terrorist activities in 1999. He was attacked in Kot Bhalwal Jail in Jammu by a former Indian soldier convicted of murder after a row between the two men on May 3.
The attack on Ranjay happened a day after Indian prisoner Sarabjit Singh died following an assault in Lahore's Kot Lakhpat Jail. Sarabjit, sentenced to death in 1990 for involvement in a string of bombings, was attacked with bricks by other prisoners.
Foreign Office spokesman Chaudhry said Pakistan wants the Indian government to ensure the safety and security of all Pakistani prisoners in Indian jails. He noted that caretaker Prime Minister Mir Hazar Khan Khoso too had called on the Indian government to ensure the safety of all Pakistani prisoners.
"We also reiterate our call to the Government of India to hold focused discussions on the conditions of Pakistani prisoners in Indian jails and repatriate those who have already completed their sentences as per the consular access agreement between Pakistan and India," he said.
Chaudhry told a weekly news briefing later in the day that, according to estimates, there were "500 to 600 Pakistani prisoners in Indian jails".
At least 47 Pakistani prisoners had completed their sentences, he said. "We are pursuing these issues with the government of India at every level," he said.
There are at least 532 Indian prisoners, including over 480 fishermen, being held in jails in Lahore, Karachi and Rawalpindi. In Delhi, the external affairs ministry spokesman said there was an urgent need to examine recommendations made by the India-Pakistan joint judicial committee that visited Pakistani jails during April 26-May 1.
"Both sides also need to take stock of the measures currently in place for ensuring safety, security and humane treatment of prisoners in each other's jails," the spokesman said. "We would like to reiterate the offer made by us on May 3, calling for a meeting with the relevant Pakistani authorities to take immediate steps to enhance the safety, security and humane treatment of Indian prisoners in Pakistani jails," he added.