The bomb, planted by insurgents, went off at around 8.20 am at Moirangkhom petrol pump area, about 400 metres from the 1st Manipur rifles parade ground where the main function of the I-Day celebrations would be held from 9 am with Chief Minister Okram Ibobi Singh as the chief guest.
Police said the bomb, planted at road side and handiwork of insurgent outfits, was of a low intensity but sound of the explosion was heard from a distance.
Senior police officials who were present at the venue of the I-Day celebrations rushed to the spot and blocked all exit routes before checking passers-by at the nearby areas.
The site of Thursday's explosion is about one km from the residence of chief minister and police headquarters.
Official sources said there has been heavy deployment of police and central para-military forces since the explosion of a powerful grenade in front of the residence of Ibobi Singh on August 10 last in capital area in Imphal west district besides stepping up patrolling and checking of passers by.
The militant outfit People's Revolutionary Party of Kangleipak-Progressive had claimed responsibility for explosion of grenade at Singh's residence area.
Coordination committee, formed by six major insurgent organisations including PREPAK-P, have called for boycott of Thursday's Independence day celebrations.
Official sources said CORCOM have been boycotting Independence and Republic day celebrations every year for the past three decades now.