Patna, Oct 28 (PTI): Police claimed to have arrested the prime suspect involved in Sunday’s serial blasts that left five persons dead at a huge rally just before it was addressed by the Bharatiya Janata Party’s prime ministerial candidate.

“One of the accused, who is being considered as the mastermind, has been arrested till now. He has confessed how the planning took place,” said Manu Maharaj, Senior Superintendant of Police, Patna.

Tens of thousands of people had gathered at Gandhi Maidan in Bihar’s capital to hear Gujarat Chief Minister Narendra Modi, the BJP’s prime ministerial candidate.

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

Maharaj said there were six or 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.

Patna’s police chief said investigation is going on “so we can't divulge a lot of details. The accused has confessed about the crime, how it happened. He told us that six-seven teams came to Gandhi Maidan and surroundings of Patna and how they planted the bombs”.

A total of 83 people were also injured in the bomb explosions, in which timers were also used.

Meanwhile, the Union home ministry has asked all states to maintain high alert and tighten security during the festival season.

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

In an advisory sent a day after the serial blasts in Patna, 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.

Sources said the states and UTs were asked to take all precautions to foil any attempt by terrorists to indulge in subversive activities, especially in places where there are large gathering of people.

The home ministry also asked authorities in Rajasthan, Madhya Pradesh, Chhattisgarh, Delhi and Mizoram to tighten security in political rallies as there may be attempts to target such gatherings by terrorists.