NEW DELHI — A convicted Indian spy who was on death row in Pakistan has died from head injuries sustained in a jail attack by fellow prisoners, an incident that threatens to further strain relations between the nuclear-armed neighbors.
Sarabjit Singh was arrested in 1990 and later found guilty of spying and involvement in deadly bomb blasts in Pakistani cities. His family has said he hails from a border village in the northern Indian state of Punjab and had crossed the countries' frontier by mistake.
Indian Prime Minister Manmohan Singh called Singh a "brave son of India who bore his tribulations with valiant fortitude." In a statement, the premier criticized Pakistan for ignoring pleas to release Singh on humanitarian grounds and called for justice for his killers.
"This will inflame tensions between the countries," said S. Chandrasekharan, director of the South Asia Analysis Group, based in New Delhi. "There is little chance now of meaningful progress in peace talks before the next Indian elections in 2014, when there will probably be a new prime minister."
Pakistan will hold a parliamentary election on May 11. The Pakistani government said in a statement that Singh died after being given the best possible treatment and arrangements would be made to return his body at soon as possible.
The incident comes after Pakistan and India engaged in some of their most serious cross-border skirmishes in almost a decade in the disputed Himalayan region of Kashmir in January and February. The fighting strained efforts to repair ties shattered by the Mumbai terrorist strike in 2008.
Singh sustained several injuries, including a fractured skull, when attacked by prisoners in Lahore's Kot Lakhpat prison on April 26. He died shortly after midnight local time, Awais Sheikh, Singh's lawyer said in a phone interview from Lahore. Sheikh said Singh had been in a deep coma.
"The relationship has been hurt by this terrible tragedy," India's foreign minister, Salman Khurshid, told reporters in New Delhi. "It is a terrible psychological and emotional setback."
Police are investigating two prisoners over the attack, the Times of India reported. The men told investigators they attacked Singh because he carried out a bomb attack in Lahore, the newspaper said, without saying where it got the information.
India and Pakistan resumed peace talks in 2011 more than two years after they were broken off following the attack by Pakistani militants on Mumbai that killed 166 people.
The border clashes in Kashmir in January undermined a sustained bid to improve trade and ease travel restrictions. For more than a week the two countries' governments and their militaries traded accusations of deadly raids across the de facto frontier.
India last year executed the only one of 10 Pakistan gunmen to be captured alive during the Mumbai attack. It has since executed a Kashmiri man found guilty of playing a role in a 2001 raid on India's parliament.
— With assistance from Bibhudatta Pradhan in New Delhi.