New Delhi: Prime Minister Manmohan Singh said on Tuesday that there "cannot be business as usual" with Pakistan after last week's deadly flare-up along the LoC in Kashmir.

"It cannot be business as usual" with Pakistan, he told reporters on the sidelines of an Army function. "What has happened is unacceptable," he added in reference to the killing of two Indian soldiers, one of whom was beheaded. Watch: No business as usual with Pakistan, says PM

"There cannot be business as usual. I hope Pakistan will realise its mistake," said Singh while speaking to reporters in New Delhi at Army Day celebrations on Tuesday.

"Those responsible for this crime (of mutilating soldiers' bodies) will have to be brought to book. After this barbaric act there cannot be business as usual with Pakistan," Singh was quoted as saying by TV channels.

"What happened at LoC is unacceptable," said the PM.

"There will be a statement by government," he also added.

The prime minister was referring to the January 8 killing of two Indian soldiers in Jammu and Kashmir, about 600 metres away from the Line of Control (LoC).

One of the soldiers was beheaded and his head taken away by the raiders. The other soldier's body was mutilated, Indian officials say. The brutality has outraged India.

Watch: No business as usual with Pakistan, says PM