Home Minister P Chidambaram on Thursday said that Afghanistan and Pakistan are the epicentres of terrorism. He said, four out of five major terrorist groups are based in Pakistan and three of them continue to target India.Addressing a conference of State Police Chiefs in New Delhi, Mr Chidambaram said that no country in the world is immune from terror attacks including the United States and the worst affected by terrorism are Iraq, Afghanistan and Pakistan.Mr. Chidambaram also said that many home grown terror groups have acquired the capacity to make bombs. He conceded that the recent blast in Delhi and Mumbai is a blot on government's record.The Home Minister described left wing extremism as a challenge to the country and there is no decline in the Naxal violence in Jharkhand and Bihar. Mr Chidambaram, said, however, there is a decline in communal violence in recent years in the country.The Home Minister said that country's security forces are being modernized to deal with multiple threats. He also suggested that violence in Tribal areas should be dealt with non-lethal ways. Mr. Chidambaram also emphasized on the need of communication between different investigations agencies to check the delays in any probe.Giving details of the investigations in the blast cases, he said chargesheets have been filed in 37 cases out of the 48 in last ten years and NIA is carrying further investigations in the blasts in Karnataka, Delhi and Mumbai.AIR correspondent reports that the conference will prepare a broad outlook to deal with terrorism, extremism and left wing extremism besides effectively dealing with communal violence. The conference has been organised by the Intelligence Bureau.