Eleven people were reported injured by the blast in Imphal, the state capital, with five of them in critical condition, The Times of India reported. The bombing occurred just after 7:30 p.m. in an improvised camp housing men in Imphal to work on a government construction project.
Police said no arrests had been made and no militant groups had claimed responsibility for the blast.
Both Manipur and Assam are in a region of India isolated from the rest of the country and surrounded by other states, including Myanmar and Bangladesh. Separatist groups have sprung up in both states.
Manipur is classified as a "sensitive area" by the Indian government. Foreign tourists require special permission to travel there.