While the first explosion took place at the Manipur Rifles Complex at 7.27 AM, the second was reported at Nambul area at 10.15 AM and the third at Konung Mamang area in the heart of the Manipur capital complex at 10.55 AM, officials said.
No casualty was reported, they said.
Investigation was on to find out how the explosions took place in the high security areas.
Major insurgent organisations, including the United National Liberation Front, have called for a boycott of the Republic Day celebrations in the state.
The organisations have urged people not to take part in the celebrations.
In view of the boycott call, security measures were tightened particularly in the four valley districts of Imphal East, Imphal West, Bishenpur and Thoubal.
Imphal: Insurgents exploded three grenades in the high security areas of the state capital on the eve of Republic Day on Friday.
First Published: Friday, January 25, 2013, 13:33