Militants attacked the private residence of Manipur Assembly Speaker Maniruddin Shaikh on Wednesday by throwing a powerful bomb minutes after he left the house at Lilong area in Thoubal district.
Shaikh lives at his official residence at Imphal.
Sources said three youths sustained injuries by splinters from the bomb. Their condition was stated to be critical.
The police was investigating whether the incident was related to monetary demand by militants from the speaker, sources said.