Pragatisheel Chhatra Jote, a platform of leftist student groups, organised the demonstration on Friday evening after daylong protests.
Leaders and activists of the student groups said the police attacked their peaceful programme, charged baton after switching street lights off and fired tear gas shells.
Witnesses said the police stopped the students outside the National Museum from marching in procession with torches from Dhaka University’s TSC towards Shahbagh.
At one stage of an altercation, the law enforcers switched off the street lights and began beating up the protesters with baton.
The police personnel fired tear gas shells when the demonstrators started throwing brickbats. The demonstrators then moved back to the campus and clashed with the law enforcers.
As many as 30 leaders and activists were injured in the attack and took treatment at Dhaka Medical College Hospital, he said and added they will demonstrate on Saturday against the attack.
Sajjadur Rahman, deputy commissioner of Dhaka Metropolitan Police, said,
“Demonstrations continued under several banners and platforms since morning. It’s alright to demonstrate, but finally the police came under attack. We tackled the situation with patience.”
He said the police asked the marching protesters to turn back when they reached near the National Museum. “They attacked the police with the torches. The police then dispersed them for self-defence.”
He denied injuring any protester. “The police only pushed them back and fired four to five tear gas shells when they threw brickbats.”
Two demonstrators were detained at the scene. “We will release them if we find that they were not involved in the attack,” the deputy commissioner of DMP said.
Earlier, in the morning, the leftist student groups blocked the streets at Shahbagh intersection for an hour before marching away in procession.
They announced the torch procession and another programme to lay siege to the home minister’s office on Mar 1.