'Yashwant Sinha asked me what had changed between my meeting with President Zardari and the meeting with Prime Minister Gilani,' Manmohan Singh said while referring to the BJP leader's accusation of 'a complete turnaround' in the government's stand in a month's time.

'In between came the dossier which showed progress, though not adequate progress,' he said. 'Sinha also asked me do we trust Pakistan? Let me say that in the affairs of two neighbours we should recall what (US) president (Ronald) Reagan once said - trust but verify. There is no other way unless we go to war,' he said.

Manmohan Singh stressed that this was the first time that Pakistan has 'ever formally briefed India on the results of an investigation into a terrorist attack in India' and countered the opposition's attack saying this was 'far more than the NDA government was ever able to extract from Pakistan during its entire tenure despite all their tall talk.'

Making a strong pitch for continuing engagement with Islamabad, Manmohan Singh said the failure to talk directly with Pakistan will means reliance on third parties. 'That route, I submit to this august House, has very severe limitations as to its effectiveness, and for the longer term the involvement of foreign powers in South Asia is not something to our liking,' he said.

'I say with strength and conviction that dialogue and engagement is the best way forward,' he stressed. 'It's our obligation to keep the channels of communication open,' Manmohan Singh said while alluding to efforts by the US and Iran to start a dialogue and repair their ties that have been strained for three decades.

The prime minister also defended the controversial inclusion of Balochistan in the joint statement - the first time the B word has figured in any bilateral document between the two countries - Manmohan Singh said India has no interest in destabilising Pakistan.

'I told Prime Minister Gilani that our conduct is an open book. If Pakistan has any evidence, and they have not given me any and no dossier has been given, we are willing to look at it because we have nothing to hide,' he said.