Plumes of smoke above the crowd after one of the blasts near Narendra Modi's rally in Patna

Five people were killed and at least 80 injured in seven crude bomb explosions in Patna before Narendra Modi arrived to address thousands of supporters and launch his party's campaign for the national election, due by May.Mr Modi is the BJP's candidate for Prime Minister.The first blast took place at the train station at 9:30 am. Six others took place within an hour at Gandhi Maidan, the large park where Mr Modi later delivered an hour-long speech that did not refer to the explosions.Five other bombs were defused, said officials.The probe will be handled by the National Investigating Agency which handles terror and suspected terror attacks.The string of explosions construe major ignominy for Bihar Chief Minister Nitish Kumar, who ended his party's alliance with the BJP in August over its decision to give Mr Modi the starring role in its campaign for the national election.However, at a press conference in the evening, the Chief Minister said that security arrangements were not inadequate. He stressed that there were no intelligence alerts about the possibility of explosions and said "what happened today is the collective responsibility of all parties" and "a lesson not just for Bihar, but for all of India." ( Read One person, who was allegedly running way from the train station where the first blast took place at 9:30 am, has reportedly confessed to planting the bombs. Two others have been caught in Ranchi with huge quantity of cash and explosives.The five people reported dead so far were at Gandhi Maidan, where TV cameras showed plumes of smoke and the crowd running in a brief period of chaos which subsided. By the time Mr Modi and other BJP leaders arrived on stage. ( Read: Bomb explodes at Modi's rally in Patna

The bombs were allegedly detonated using timers and appear similar to those used in a terror attack in the pilgrimage town of Bodh Gaya in Bihar in July, said senior police officers. ( Read: Centre seeks report, rushes NIA team