Twenty-four activists of Islami Chhatra Shibir, student organisation of Jamaat-e-Islami, have been held in Kishoreganj.
The identities of the detainees could not be known immediately.
Being informed that a group of Shibir men were planning to create anarchy in the town's Pyaradanga and Natun Jailkhana areas, a police team police team conducted a drive in the area, said Mohammad Daud, officer-in-charge of Kishoreganj Sadar Model Police Station.
Sensing the presence of law enforcers, they threw two crude bombs, injuring a policeman, said the OC.
Later, police arrested the Shibir men from the spot.