A powerful bomb, hurled by unidentified militants, exploded inside the Manipur Assembly complex on Saturday.
No casualty has been reported yet, official sources said.
The militants who drove up to the heavily-guarded Assembly complex around 11.30 am and hurled the bomb, which exploded inside the complex, they said.
They then drove away towards Imphal-Dimapur NH39, the sources said.
No individual or militant group has claimed responsibility for the attack.
The Manipur assembly is located in the heart of Imphal town and is surrounded by market, VIP quarters and NH 39.
All exit routes have been blocked and police is checking vehicles and passers by.