PATNA: Making headway in the Patna blasts case, police have arrested two suspected terrorists, including one possibly the mastermind , and detained several others, even as the toll in the serial explosions rose to six.

A search operation by NIA and Patna Police is on at Gandhi Maidan, the area which witnessed six of the seven serial bomb blasts on Sunday that left 83 people injured, to locate explosives, if any, a senior police officer said on Monday.

The suspected terrorists have been identified as Tausim and Imtiyaz, official sources said.

SSP Patna Manu Maharaj earlier said that "one of the accused, who is being considered as the mastermind, has been arrested. He has confessed how the planning took place".

Three to four suspects have been detained, he said, adding, "We are in the process of interrogation so things will be clear very soon".

Maharaj said there were six-seven persons accompanying the alleged mastermind.

"Based on that information, we conducted raids. Information was given to Ranchi and subsequently our teams have gone there," he said.

Six persons were killed in the seven low intensity serial blasts of which six bombs went off in and around the venue of BJP prime ministerial nominee Narendra Modi's mega rally at Gandhi Maidan shortly before his address before a huge gathering yesterday.

Patna city SP said the investigation is going on "so we can't divulge a lot of details. The accused has confessed to the crime and how it happened. He told us that six-seven teams came to Gandhi Maidan and surroundings areas of Patna and how they planted the bombs".

Meanwhile, the toll in the serial blasts rose to six after an injured person died at the Patna Medical College and Hospital (PMCH) on Sunday night.

Currently, 37 injured persons, many of them in critical condition, are being treated in the hospital.

Raids were being conducted in several areas of neighbouring Jharkhand on Monday in connection with the blasts.

Three persons detained after the blasts yesterday were released after interrogation last night, a senior police officer said in Ranchi.

Police recovered black powder, materials used to make IEDs, pressure cooker and extremist literature during the raids, he said.

In the wake of the multiple blasts in Patna, the Centre has asked all states to maintain high alert and tighten security during the festival season.

The home ministry also asked five poll-bound states to beef up security in election rallies, especially those being attended by top leaders.

The home ministry asked the states and union territories to keep strict vigil on sensitive places, markets, religious sites, railway stations, bus terminus and in other vital installations besides deploying adequate forces for their security.

