In what is his first response to the recent escalation of tensions with Pakistan, Indian Prime Minister Manmohan Singh on Tuesday said that it "cannot be business as usual with Pakistan."

Speaking off the camera to journalists in the national capital, the PM when asked about options vis-a-vis Pakistan, said, “it cannot be discussed in the open.”

However, talking in a tough language, he added, “Those responsible for this crime (of mutilating soldiers' bodies) will have to be brought to book.” Asked about Pakistan being in denial mode, Manmohan Singh said, “I hope Pakistan realises this".

Earlier today, the process of issuing visas on arrival to Pakistani senior citizens at Wagah, that was to have begun, was delayed. There is immediate speculation on whether the sudden move is linked with tension with Pakistan along the Line of Control in Kashmir.

The government has so far resolutely said that the recent tension will not derail the liberalised visa agreement signed between India and Pakistan last year.

Visa on arrival for Pakistanis over the age of 65 at the Attari-Wagah border joint check post is part of that agreement and Home Minister Sushil Kumar Shinde said last week,  "We are not rethinking the agreement. Whatever agreement we entered into, we will honour that." 

Government officials said today that this was a technical delay caused by last-minute clarifications sought by some agencies on whether Pakistani senior citizens who get this visa need to have a sponsor in India.  

The government is also reaching out to the BJP leaders as an attempt to get the opposition on board and ensure political consensus on policy.

National Security Advisor Shiv Shankar Menon briefed BJP leaders Arun Jaitley and Sushma Swaraj this morning on the situation at the Line of Control (LoC) in Kashmir.

Sources said the BJP leaders have asked the government to act tough with Pakistan over the ceasefire violations in the last week and have also assured it of the opposition party's support.

The meeting, held at Ms Swaraj's residence in Delhi, lasted 45 minutes.

On Monday evening, Prime Minister Manmohan Singh had called the two senior BJP leaders to discuss the Pakistan issue and assured them that his government would keep them in the loop. Mr Jaitley is the Leader of the Opposition in the Rajya Sabha, Ms Swaraj in the Lok Sabha.