The abandoned suitcase was found on the highway, about 10 kilometres from Dhekiajuli town and the local people informed the security forces about it, a defence spokesman said.
Police and Assam Rifles (AR) personnel rushed to the spot and cordoned off the area.
The AR personnel along with Army Engineers team conducted investigations and confirmed the presence of explosives in the suitcase, he said.
The team then carried out a two hour-long operation to destroy the suitcase without opening it along with the explosives.