The BJP on Monday condemned Sunday's serial blasts in Patna and charged the Bihar government of being "soft on terror".
"We condemn the blasts...there should be an investigation into it," Bharatiya Janata Party (BJP) leader Arun Jaitley said at a press conference.
Jaitley accused the Bihar government of "being soft on terror" and criticised chief minister Nitish Kumar's Sunday statement that no specific intelligence was available about the blasts.
"...security is the responsibility of a state government," he said, adding "we are living in a vulnerable security environment".
Six of the seven explosions occurred at the venue of BJP's prime ministerial candidate Narendra Modi's rally in Patna on Sunday.
The BJP leader noted gaps in police security arrangements at the rally.
The toll in the serial blasts in the Bihar capital went up to six on Monday following the death of a bomber who was seriously injured in an explosion while setting up an explosive device at the railway station.