Three crude bombs were hurled at a rally of Ganajagaran Mancha in Sathmatha area in Bogra on Friday evening.
Sources said three crude bombs were hurled at a rally organised for Ganajagaran Mancha second road march towards Panchagarh in the evening.
Sadar police station duty officer Sub-Inspector Mojida said four people were detained from the rally venue soon after the incident.
The detainees are Abu Naser, 16, Farukh Sheikh, 19, Md Ashraful, 14, and Md Tarekul Islam, 17.
Mojida said of the detainees, two were injured in mob beating.
However, Ganajagaran Mancha Convener Imran H Sarkar will be speaking in the rally at night.
