Gorkha Janmukti Morcha (GJM) assistant general secretary Benoy Tamang was arrested Thursday along with six of his party workers from near the West Bengal-Sikkim border in Darjeeling district, police said.
"Tamang and the others were rounded up from Rangpo in connection with cases like putting up road blockage and preventing police officers from carrying out their duties," Kalimpong sub-division Additional Superintendent of Police Sangmit Lepcha said.
Tamang, a close associate of GJM supremo Bimal Gurung is the highest-ranking leader of the party to be arrested since the West Bengal government started a crackdown on its leaders.
Forty GJM activists were taken into custody since Wednesday night, district Superintendent of Police Kunal Agarwal said.
Since the party began a fresh agitation for the carving of a separate Gorkhaland in the wake of the announcement of the formation of Telangana last month, 710 GJM activists have been arrested.