Mr Chidambaram told newspapers in New Delhi he would take 'overwhelming' and 'unanswerable' proof to Washington for discussions with US officials.

'The evidence leads to the conclusion that the plot was hatched in Pakistan and as the operation in Mumbai was on, it was masterminded and controlled from Pakistan,' the Indian Express quoted Mr Chidambaram as saying.

He said the 'detailed dossier' included telephone transcripts, communication intercepts and interrogation reports.

India has blamed 'elements' in Pakistan for the attacks in late November, saying that the Islamist group Laskhar-e-Taiba trained and equipped the militants who stormed India's financial capital.

But Pakistan has repeatedly said that New Delhi has provided no proof of this involvement in the strikes.

Keeping up the pressure on Pakistan, India's Prime Minister Manmohan Singh said on Saturday that he hoped Pakistan would show 'better sense' and crack down on militant groups blamed for the attacks. -- AFP