"The four National Democratic Front of Bodoland-Songbijit and RNLA extremists were nabbed from Murabari village in Harisinga police station during a joint operation last night," IGP L R Bishnoi told PTI.
"A factory-made revolver, two rounds of AK-47 live ammunition, a khukri (knife), Rs 36,500 in cash, four mobile handsets, 9 SIM cards and four mobile memory cards were recovered from them," he said.
The ultras were engaged in extortion in Kalaigaon, Harisinga and Khairabari areas of Udalguri as well as Goreswar area of neighbouring Baksa district, Bishnoi said.