New Delhi, Sep 6 - Home Minister P. Chidambaram Sunday said that Pakistan's unwillingness to prosecute the mastermind of the 26/11 Mumbai terror attack Hafiz Saeed is 'atrocious'.

'(While) covering up is a very strong word, there is for some strange reason (an) unwillingness to take investigation forward (by Pakistan),' Chidambaram told private news channel NDTV in an interview to be telecast Monday.

'In the face of this evidence, to let him off, i think, is atrocious...'

The attack on Mumbai Nov 26, 2008, by ten terrorists left 170 people dead. India holds Lashkar-e-Toiba chief Hafiz Saeed responsible for orchestrating the carnage.

The home minister's statement comes after Pakistan last week trashed the sixth and latest dossier India gave as being a 'rehash' of earlier information on Hafiz Saeed and which Pakistan deemed as inadequate to start a prosecution.

The home minister said that India had shared this dossier with 16 other countries, whose nationals had died in the Mumbai attacks that lasted over 60 hours.

Chidambaram, who leaves for the US Monday on a four-day visit, said he will take up the matter with the Obama administration.

'Yes, so they (the US) know what we have. If there is an opportunity, I will take them through the dossier to point out that there is enough evidence to continue the case against Hafiz Saeed,' he said.

Revealing details of what India had given in the dossiers, Chidambaram said: 'We know when (lone surviving terrorist Ajmal Amir) Kasab first met Hafiz Saeed and where. We know what Hafiz Saeed told the trainees. We know at least a couple of places where the training took place and that Hafez visited those training camps'.

Further, India has said Hafiz Saeed had also given the terrorists aliases as well as tested their skills.

'We know that he (Saeed) was accompanied by a person described as major general sahib.