The Pakistan High Commissioner in New Delhi Salman Bashir Monday visited critically injured prisoner Sonaullah undergoing treatment in the intensive care unit of Post Graduate Institute of Medical Education and Research (PGIMER) Hospital in Chandigarh city, officials said.

"The Pakistan High Commissioner this afternoon visited the patient Sonaullah at advanced trauma center here," said Manju Wadwalkar, the public relations officer of PGIMER hospital at Chandigarh. "He was briefed in detail about the patient's status right from his arrival to the present condition by Prof. S N Mathuriya, HOD, Neurosurgery and Prof. Y K Batra in charge ICU in the presence Director and Medical Superintendent of PGIMER."

The 52-year-old Sonaullah suffered multiple head injuries Friday morning after being attacked by another inmate inside Kot Balwal jail of Indian-controlled Kashmir. Following the attack he slipped into deep comma and was airlifted to PGIMER Chandigarh, a premier health institute in north India.

The attack on Sonaullah was seen as an apparent retaliation to the death of a convicted Indian spy Sarabjit Singh on Thursday. Singh was assaulted by a fellow prisoner inside a Pakistan's Lahore prison on April 26.

Meanwhile, Sonaullah continues to be on ventilator in critical condition for the fourth straight day.

"He appears bit more critical than yesterday," said Wadwalkar. "His neurological status continues to be the same without any improvement."

Indian officials say there are 535 Indian prisoners in Pakistani jails and 272 Pakistani prisoners in Indian jails.

According to Syed Akbaruddin, the spokesman of India's Ministry of External Affairs, India was proposing a meeting of officials in both countries to "identify and put in place further measures to avoid such tragic incidents in future."