With a combative opposition accusing him of going soft on 26/11 terror, Prime Minister Manmohan Singh on Saturday said he was optimistic about the resumed peace process with Pakistan, but stressed that he has made it clear that if another ‘barbarous’ Mumbai attack were to happen, it will be a ‘setback’.

"I did discuss (with Pakistani Prime Minister Yousuf Raza Gilani) the Mumbai terror attack. Those who perpetrated the barbarous attack must be brought to justice," Manmohan Singh told reporters on board his special aircraft while returning from the SAARC summit in the Maldives.

"I left Prime Minister Gilani in no doubt that if public opinion in India is not satisfied that justice is being done to those responsible to the barbarous attack, it won't be possible to move forward with the peace process," said Manmohan Singh.

"We both recognize that if there is another attack like Mumbai, it will be a setback to the normalization of relations. And that was understood by Prime Minister Gilani," said the prime minister.

The prime minister's clarification came two days after he held wide-ranging talks with his Pakistani counterpart on the sidelines of the SAARC summit and amid the Bharatiya Janata Party's accusation that he has gone soft on terror emanating from Pakistan barely days before the third anniversary of 26/11 attack.

Striking an upbeat note, the two leaders vowed to write a new chapter in relations between India and Pakistan and hoped that the next round of the dialogue will be more constructive and result-oriented.

Pointing out that the relations between India and Pakistan are "subject to accidents," Manmohan Singh took positive note of the decision of Pakistan to grant Most Favoured Nation status to India and stressed on encouraging development in areas like trade and the willingness of Pakistan to discuss all issues, including that of terror.

"I told him (Gilani) that terror as an instrument of state policy has no takers in the world and it has given rise to Pakistani terrorism. Terror has to be dealt with firmly," he said.

In these areas (trade and terror), it is possible to find the way forward, he said.

"Trade and economic relationship is one area where progress is possible.

"The thinking people in Pakistan realize that trade is a win-win situation," he said.

Manmohan Singh also underlined that the powerful Pakistani Army was fully on board in carrying forward the resumed peace process.

"I did discuss with Prime Minister Gilani whether the Pakistan Army is fully on board to carry forward with the peace process," he said.

"The sense I got was that after a long time, Pakistan's armed forces are fully on board," he said.

Reacting to criticism back home about his describing Gilani as a man of peace, Manmohan Singh said: "I have met Prime Minister Gilani four-five times. He agreed with me that there is not way but to find a peaceful resolution of all outstanding issues."

"I, therefore, believe that Pakistan has a democratic government and we will like to strengthen the hands of democratic government," he said "In Gilani, we have a prime minister who we can work with," he said.

However, Manmohan Singh pointed out that his decision to resume the peace process with Pakistan was not individual-centric.

"Our approach to Pakistan is trust but verify. We are not putting blind faith in one individual. I do hope it will genuinely lead to the normalization of relations," he said.

"If our government gets solid evidence that terror is continuing (from Pakistan), it will be a negative factor. If trade relations move positively, it will be a positive factor," Manmohan Singh said.

"I come back with the expectation that the second round of resumed dialogue which will commence very soon will have the advantage of more informed dialogue. I am optimistic," he said.