Police said the incident took place late Thursday at Sat Kilo area in the hill district.
Police found the damaged car with two burnt bodies Friday morning.
“It appears the two were carrying the bomb to some place when it exploded, killing both,” a police officer said. “The victims are yet to be identified.”
Meanwhile, police recovered a grenade from near a bus stand in Dhekiajuli town in northern Assam Friday morning.
Police said suspected militants lobbed two grenades at an oil depot in the same town Thursday. One exploded, injuring a boy.
Security forces have warned that militant outfits in Assam, including the anti-talk faction of the United Liberation Front of Asom (ULFA), may carry out terror attacks to mark India’s Republic Day Jan 26.
Twelve militant groups in India’s northeast have called for a general strike Jan 26 and asked people to boycott Republic Day functions.