Accepting it as a "mistake" and taking "responsibility", home minister P Chidambaram today said the inclusion of terror accused Wazhul Kamar Khan in the list of most wanted fugitives given to Pakistan was a "genuine error" by Mumbai Police and "oversight" by the Intelligence Bureau.

Addressing a press conference a day after the goof up was exposed in the media and facing attack, he contended that it was not such a "monumental mistake" of "calamitous consequence" and said he was prepared to face some "political exchanges" on the issue.

"We take responsibility. It is a mistake. How this mistake has happened has been explained subsequently. CBI through Interpol will notify the arrest of Khan," he said, adding his name has already removed from the list of wanted men.

Giving details of the events that led to the "lapse" as he termed it, Chidambaram said it now transpired that the Mumbai Police arrested Khan, an accused in 2003 Mulund blasts, on May 21, 2010.

However, this information of arrest and the request for consequent Red Corner Notice was not sent by the Mumbai Police to the CBI. There were further enquiries by CBI with Mumbai Police on Khan on January 27 this year.

The Mumbai Police replied to the query yesterday requesting cancellation of the Red Corner Notice as Khan was no longer required by Mumbai Police on account of arrest last year.

However, the Home Minister revealed that it has been gathered that the Mumbai Police had in January this year conveyed to IB office in Mumbai that Khan had been arrested.

"This information, unfortunately, was not reflected in the list of fugitives maintained by the authorities and was overlooked while a list was prepared in March 2011," he said.

Chidambaram said it would therefore be clear that the failure to formally communicate the fact of the arrest of Khan on May 21 last year to CBI has resulted in the name being retained by CBI.

"It is possible that the said failure was the result of a genuine oversight by the Mumbai Police. At the same time there was also a lapse on the part of IB in not reflecting the information received by it while preparing the list in March 2011," he said.

Replying to a question whether Khan had travelled to Pakistan, Chidambaram said his name had figured in 2007 list of wanted. Now Khan has claimed that he has lost his passport and this will be probed, he said.