Bosnian authorities said they will shut down Muslim groups that advocate extremism and refuse to affiliate with the state-recognized Islamic Community organization by March 1.
The move to shut down extremist groups on February 26 came after IS issued a death threat earlier in the week against Bosnia's top Islamic cleric, Grand Mufti Husein Kavazovic.
Dozens of groups have formed outside the official structure in recent years, attracting an estimated 3,000 followers mostly in rural areas. Some pursue radical interpretations of Islam not traditional among Bosnia's nearly 2 million Muslims.
Police say such illegal groups have become hotbeds of Islamic radicalism, sending an estimated 150 members to Syria to join the Islamic State (IS) group.
Moreover, police estimate that more than 50 IS fighters have returned to Bosnia, where they could carry out missions on IS's behalf.
The Islamic Community on February 26 urged members of such groups to abandon self-proclaimed imams who are luring people into a "monstrous" ideology. Last month, the community sent envoys to the groups urging people to switch to an official congregation.