(at Jinnah Hospital) at 1 am (1:30 IST) informing me that Sarabjit is no more," Mahmood Shaukat, the head of a medical board that was supervising 49-year-old Sarabjit's treatment, told PTI.
Pakistani police arrive to cordon off a hospital in Lahore following the death of Indian death row prisoner Sarabjit Singh. (AFP)
Another doctor, who was part of the team treating Sarabjit, said he died of cardiac arrest, adding that doctors made several unsuccessful attempts to resuscitate him.
Officials of the Indian High Commission in Islamabad said they had been informed by officials of Jinnah Hospital about Sarabjit's death.
Sarabjit sustained severe injuries when at least six prisoners attacked him in a barrack at Kot Lakhpat Jail on Friday, hitting him on the head with bricks.
In New Delhi, Prime Minister Manmohan Singh expressed sadness over Sarabjit's death, saying criminals responsible for the barbaric and murderous attack on the Indian national must be brought to justice.
Sarabjit was convicted of alleged involvement in a string of bomb attacks in Punjab province that killed 14 people in 1990 and spent about 22 years in Pakistani prisons.
Sarabjit Singh's wife Sukhpreet Kaur at Attari border. His sister Dalbir Kaur and daughters Swapandeep and Poonam are also seen. HT/Munish Byala
Sarabjit was on life support since April 26.
His family, who had just returned to India after visiting him in Jinnah hospital, always insisted Sarabjit was innocent and he had inadvertently strayed across the border in an inebriated state.
His mercy petitions were rejected by the courts and former President Pervez Musharraf. The previous Pakistan People's Party-led government put off Sarabjit's execution for an indefinite period in 2008.
Sarabjit's heart was beating "but without brain function" because of the extensive head injuries he sustained during the assault. He was completely unresponsive and unable to breathe without ventilator support.
Shaukat said authorities were yet to decide on conducting an autopsy on Sarabjit's body. Asked whether the autopsy would be done after getting
permission from the government, he said: "At the moment I have no idea."
No decision had been made about handing over the body to Sarabjit's kin or to Indian authorities, Shaukat said.
"These matters will be worked out according to the directions from the government," he said. The official sources in Lahore had yesterday said
Sarabjit had slipped into a "non-reversible" coma and this could lead to "brain death".
His measurements on the Glasgow Coma Scale, which indicates the levels of consciousness and damage to a person's central nervous system, had dropped to a "critical level", the sources said.
Police have booked two death row prisoners Amer Aftab and Mudassar for the attack on Sarabjit. They reportedly told investigators that they had attacked Sarabjit because he had allegedly carried out bomb attacks in Lahore.
No action has been taken so far against officials of the jail for failing to provide adequate security to Sarabjit. Following the rapid deterioration in Sarabjit's condition, New Delhi had requested that he be immediately released so that he could be treated in India or a third country.
Pakistan had said it was "positively considering" the request to repatriate Sarabjit. Prime Minister Singh today said the Indian government
will make arrangements to bring Sarabjit's remains home and for his last rites to be conducted in consultation with his family.