The curfew was imposed after police arrested Bodoland Peoples' Front (BPF) MLA Pradeep Brahma in the wee hours Thursday for his alleged role in the communal violence.
Brahma was remanded to judicial custody by a Kokrajhar court.
Today, the BPF called for an indefinite bandh of Kokrajhar district protesting the arrest of Brahma. The BPF, a partner of the ruling Congress in Dispur, has also threatened to snap ties with the Congress.
The party is, however, yet to make its stand clear officially.
Police said Brahma was arrested after seven cases were registered against him in two police stations in the district alleging his role in the violence between the Bodos and Bengali-speaking Muslim settlers that rocked three districts of Western Assam-Kokrajhar, Chirang and Dhubri, killing 77 people and displacing over four lakh people.
The BPF is in power in the Bodoland Territorial Council (BTC) that runs the administration in four districts of BTAD.