Even as Congress spokesman Manish Tewari today expressed regret over his remarks against Anna Hazare, the Gandhian's lawyer said a case of defamation would be filed against the Lok Sabha MP in a court here next week.

"We will file a case against Manish Tewari under IPC Section 500 for the defamatory remarks made by him against Hazare on August 14, describing him as a corrupt person at a public forum," advocate Milind Pawar told PTI here.