The militants, under the banner of the 12 Islamist parties, were actually Jamaat-e-Islami activists, senior police officials said.
The Deputy Commissioner of Sylhet Metropolitan Police, Ejaz Ahmed, told bdnews24.com, a group of “religious hardliners” entered the Shaheed Minar with a procession at around 2:45pm and set on fire the flowers offered there on the occasion of the International Mother Language Day on Thursday.
They also smashed the Shaheed Minar boundary wall, Mujib-Jahan Blood Bank and the BMA building, the police said.
The area between Zindabazaar and Chouhatta turned into a virtual battle ground as the militants fought pitched battles hurling brickbats at the law enforcers.
At least 10 persons, including several journalists, sustained bullet injuries, the police said.
Police reportedly fired several rounds of teargas shells, sound grenades and shotgun bullets to gain control of the situation.
Deputy Commissioner Ahmed said the law enforcers have been put on alert after the incident.