Union Home Secretary RK Singh has said the Pune serial blasts appeared to be a planned and coordinated act. Talking to media persons in New Delhi on Thursday, he said the blasts took place within an area of 500 meters and in a span of 45 minutes.

Home Minister Sushil Kumar Shinde said investigations in connection with the blasts were underway. Two teams from the National Investigation Agency (NIA) and bomb disposal experts will investigate the motto behind the blasts and device used to trigger them.

Official sources New Delhi said the technique adopted in the blast was similar to the technique adopted by the terror outfit Indian Mujahideen, which has links with terror groups in Pakistan.

People who are witness to the blast are being questioned, including the lone person injured in the blast.

Maharashtra Home Minister RR Patil reviewed the progress in investigations with top police officials on Thursday. Chief Minister Prithviraj Chavan also held a meeting of senior officials to step up security for Mumbai in the wake of the blasts. Several state governments have sounded alert following the explosions.

AIR correspondent reports investigating agencies have begun to gather evidence in the blasts. Joint Commissioner of Police Sanjeev Kumar Singhal said that a joint team of Crime Branch and Anti- Terrorism Squad has been formed and they are examining all the possibilities.

However, he made it clear that it was not possible to arrive at a conclusion at the moment. He said no arrest had been made in that connection so far.