Indian national Sarabjit Singh, currently on death row in a Lahore jail, was on Friday seriously injured on the head and rushed to Jinnah Hospital for an emergency surgery after being attacked by a fellow prisoner.
Sarabjit was admitted to the state-run Jinnah Hospital after being attacked within Kot Lakhpat Jail.
The attack reportedly occurred while Singh was being moved from one cell to another.
He sustained a head injury and was initially taken to the hospital within the prison. After his condition worsened, 49-year-old Sarabjit was taken in an ambulance to Jinnah Hospital.
There was no official word on the incident.
Reports said he has undergone a CT Scan and will soon be operated upon by doctors.
Meanwhile, Ministry of External Affairs Spokesperson Syed Akbaruddin said in Kazakhstan, where he is accompanying External Affairs Minister Salman Khurshid on a visit, that India has sought consular access.
"India has contacted Ministry of Foreign Affairs in Pakistan for ascertaining the facts. Two officers have been sent to Lahore for consular access and we are awaiting response. We are in touch with the Foreign Ministry and the Presidency," Akbaruddin said.
Owais Sheikh, Sarabjit's lawyer said, "Yes, this is very much disturbing. This is not something that we can ignore. Naturally, this will have very very serious consequences. "Whatever has happened, our jail authorities are responsible for that. Hope god saves Sarabjit Singh. He has been seriously hurt".
Officials of the Indian High Commission said that they had not been informed by Pakistani authorities about the incident. The Kot Lakhpat jail currently has some 17,000 prisoners though its official capacity is only 4,000.
There have been instances in the past of prisoners being attacked and even killed within the prison. Authorities had tightened Sarabjit's security after the recent execution of Afzal Guru, who was convicted of in the 2001 Parliamen attack case.
Sarabjit was convicted for alleged involvement in a string of bomb attacks in Punjab province that killed 14 people in 1990. His mercy petitions were rejected by the courts and former President Pervez Musharraf.
The outgoing Pakistan Peoples Party-led government put off his execution for an indefinite period in 2008. His family says he is a victim of mistaken identity and had inadvertently strayed across the border in an inebriated state.