Indian prisoner Sarabjit Singh attacked in Lahore jail

A prisoner convicted of spying for India was attacked and seriously injured by fellow inmates in a Pakistani jail on Friday in an incident that could inflame the uneasy relations between the two nations.

Sarabjit Singh was hospitalised with a serious head injury, a doctor said, after two fellow prisoners attacked him in Kot Lakhpat Jail in Lahore.

"Sarabjit was having tea with fellow prisoners Muhammad Muddasar and Amir, also condemned for death sentence in murder cases. They exchanged hot words with Sarabjit and attacked him with bricks and blades," jail official Munawar Ali said.

Singh was arrested in Pakistan in 1991 and sentenced to death for spying and carrying out four bomb blasts that killed 14 people. His family says he is innocent.

Four years ago, Pakistan's then-president Pervez Musharraf stayed the execution after appeals for clemency from India's Prime Minister Manmohan Singh.

Nuclear-armed India and Pakistan have fought three wars since the partition of British-ruled India in 1947, but they began a peace process in 2004.

Despite better relations, the neighbours remain deeply suspicious of each other.

India blamed Pakistani militants for carrying the 2008 attacks in Mumbai that killed 166 people over three days and raised questions over the involvement of Pakistani security services.