NDFB militants exploded a bomb near a railway track in Sonitpur district of Assam on Wednesday night, but there was no casualty or damage.
Official sources said two militants from the banned group came to plant a bomb on a railway bridge at Thainabad in Dhekiajuli when they encountered security personnel.
The militants then exploded the bomb 20 metres away from the bridge near the railway track, they said, adding there was no damage or any casualty.
The militants fled to nearby Arunachal Pradesh, they added.
Earlier, the NDFB had threatened to target railway tracks and roads in Tezpur and Udalgiri districts.
Patrolling was intensified and security checks are being carried out at rented premises in Tezpur town.
