Five low-intensity blasts occurred in the city on Sunday, reports said.
According to reports, at least one person was killed as a crude bomb exploded in Patna railway station earlier in the day.
It was the first blast that rocked the city ahead of Modi's 'Hunkar Rally' in Patna.
Other blasts occurred around Patna's Gandhi Maidan where over 25,000 people had already gathered by then to attend Modi's rally.
The police have detained one person so far.
"Union Home Ministry will send a team of seven-member team of National Investigation Agency (NIA) and National Security Guards (NSG) officials to investigate multiple bomb blasts in Patna," CNN-IBN reported.
Bihar Chief Minister Nitish Kumar has reportedly called for an emergency meeting of senior police officers to take stock of the situation after the blasts.
Modi is addressing the rally just months after the Janata Dal (United) [JD-U] announced its decision to sever ties with the BJP, ending a 17-year-old alliance and drawing clearer battle lines ahead of national elections less than a year away.
--IBNS (Posted on 27-10-2013)