He also said that Pakistan's offer of joint investigation will be relevant only when it admits that Amir Ajmal Kasab, the lone terrorist caught during the Mumbai attacks, is a Pakistani citizen.

Chidambaram, who is scheduled to visit the US next week, said, "Pakistan's offer of joint investigation is a meaningless offer. Pakistan's offer is relevant only when it admits that Kasab is a Pakistani citizen and Kasab's handlers were Pakistani.

"They have never admitted that. Why do you want to jointly investigate something with which you say your citizens have no connection at all?" he asked.

Replying to questions, the Home Minister said "somebody who is familiar with intelligence and who is familiar with commando operation has directed this (Mumbai) operation. And that cannot entirely be a non-state actor.

"In fact, I presume they are state actors or state- assisted actors unless the contrary is proved. It is too enormous a crime and required elaborate planning, communication networks and financial backing. It was a very, very sophisticated operation."

On the issue of evidence in the form of Kasab's DNA, the Home Minister said, "his DNA is available...Now there is a person in Faridkot village in Pakistan who says he is his father. His DNA is available in Pakistan. So if somebody matches the DNA, we will know who is right and who is wrong."

Pakistan, he said, knew the kind of evidence which India has on Mumbai strikes.

"Pakistan is in total denial because it knows that it will be completely embarrassed if the truth comes out and the truth will come out, whether Pakistan likes it or not. Denials are getting weaker and denials are becoming hollow now."