The militants exploded two IEDs between two tea gardens at Kherbari Tiniali when jawans of the 4th Rajput Regiment were moving in three trucks to Naharkatia at about 7.30 am, police officials said.
One jawan was seriously wounded and has been hospitalised. A truck was also damaged in the explosion, they said.
The IEDs were exploded by remote control as long wires were found in the area. A bag was also recovered from the spot, but its contents would be known after bomb experts examined it.
Many tea bushes of the tea gardens on both sides of the road were burnt under the impact of the explosion, they said.
The local people claimed that the sound of the blast could be heard about half a km away.
The Paresh Baruah-led ULFA (I) in an email to the media claimed responsibility for the blast.
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Assam: 3 ULFA militants killed in blast