Indian Prime Minister Manmohan Singh on Thursday urged Pakistan to "bring to justice" as many as six inmates accused of attacking Indian Sarabjit Singh inside a Lahore jail last Friday and leaving him with multiple injuries.

Singh died at Lahore's Jinnah hospital on Wednesday while still in a coma.

The Indian prime minister said it was "'particularly regrettable" that Pakistan had not heeded Indian pleas to release Sarabjit Singh two years ago on humanitarian grounds after he had served 20 years in prison

In the Indian parliament opposition deputies accused Prime Minister Singh's government for being too soft on Pakistan. Parliament was adjourned for two hours after deputies shouted anti-Pakistan slogans.

Motive unclear

Pakistani police said Singh was hit with bricks and other blunt objects by inmates whose motive was unclear. At least two suspects were arrested after the attack.

In 1991 Pakistani authorities passed a death sentence against Singh on charges of being involved in espionage and several bomb attacks. Those bombings in 1990 in Lahore and Faisalabad claimed 14 lives.

His appeal for mercy was turned down, but a Pakistani moratorium on executions kept him off the gallows.

Sarabjit Singh's family had consistently maintained that he was innocent and that in 1990 he had entered Pakistan inadvertently from his hometown of Bhikiwind in northern Punjab state bordering Pakistan.

Pakistan lauds medics' efforts

The Pakistani foreign ministry said on Thursday that Pakistani authorities were completing all formalities to hand over the dead inmate's remains to the Indian high commission in Islamabad as early as possible.

Pakistan's Foreign Affairs Ministry said medical staff at the Jinnah hospital in Lahore had worked round the clock to save Singh's life.

"However, despite their best efforts, they could not save him and Sarabjit Singh passed away due to cardiac arrest," the ministry said.

The latest flare-up follows an outbreak of violence in January in the disputed territory of Kashmir, where two Pakistani and two Indian soldiers were killed.

Indian-Pakistan relations have been volatile for decades. The 2008 terror attack in Mumbai led to heightened tensions but these eased after intense international diplomatic pressure.

ipj/dr (AP, Reuters, AFP)