On a tip off, police nabbed two militants from a bus coming from Arunachal Pradesh in front of the army camp at Lakhipur in Goalpara district.
Five hand grenades, a pistol with 20 ammunition and blank cartridges of AK-47 rifle were recovered from the ultras who are brothers, police sources said.
The two have been identified as Gupesh Hajong, who was trained in an ULFA camp in Bhutan in 1997, and Durlav Hajong, the sources said.
In Dibrugarh district, another ULFA extremist Nitul Das was picked up at Chabua with five grenades, one pistol, ammunition and documents.
Interrogation of the arrested ultras were on, they added.
