SRINAGAR (AFP) - A Pakistani prisoner suffered serious head injuries on Friday after being attacked in an Indian jail in apparent tit-for-tat violence following the death of an Indian inmate in Pakistan, a prison official said.

"He has been admitted in GMC Hospital with grievous head injuries," an official at the main prison in the northwestern city of Jammu told AFP on condition of anonymity.

The inmate, named as Sanaullah, was attacked early in the morning by other inmates, the official said, a day after India's home ministry ordered stepped-up security for hundreds of Pakistanis in Indian prisons.

On Thursday, Sarabjit Singh, an Indian in Lahore's Kot Lakhpat prison, who was jailed 16 years ago for spying and deadly bombings, died as a result of a savage assault by inmates.

Indian Prime Minister Manmohan Singh condemned that "barbaric and murderous attack" and New Delhi complained that its diplomats were denied access to the prisoner as he fought for his life.

Singh is to be cremated with state honours near his native village in northwestern Punjab state on Friday.