At least four students were injured when police charged batons and lobbed tear gas canisters to disperse a demonstration of students of seven colleges in the capital's Shahbagh yesterday.

The students held the programme demanding the announcement of their examination schedules.

Police also detained 13 students on the spot. Officer-in-Charge of Shahbagh Police Station Abul Hossain claimed that the students were detained on the charge of obstructing road and damaging cars.

Of the injured, Mainul Hasan of Dhaka College and Siddiqur Rahman of Titumir Govt College were admitted to the Dhaka Medical College Hospital. Later, Siddiqur, whose eyes got badly hurt in the police action, was shifted to National Institute of Ophthalmology. The identities of the two others could not be known immediately.

Meanwhile, the authorities of the seven colleges -- Dhaka College, Eden Mohila College, Government Shaheed Suhrawrdy College, Kabi Nazrul Government College, Begum Badrunnesa Government Mohila College, Mirpur Government Bangla College, and Government Titumir College -- yesterday announced the exam schedules following the protest.

The colleges became affiliated with Dhaka University on February 16, 2017.

Talking to The Daily Star last night, IK Selim Ullah, principal of Kabi Nazrul College, said the decision on exam schedules was taken at a meeting between Dhaka University vice chancellor and principals of the seven colleges on Tuesday, and the colleges were supposed to announce the schedules.

But the college authorities informed their students only yesterday while the students were demonstrating at Shahbagh intersection.

Earlier in the morning, several hundred students of the colleges, who have been demanding announcement of exam schedules for the last few months, formed a human chain in front of the national museum at about 10:00am.

At about 11:30am, they occupied the busy Shahbagh intersection, causing traffic congestion in the area.

HM Azimul Haque, additional deputy commissioner of police, Ramna division, said the students were first requested to clear the busy intersection. “When they didn't listen, we dispersed them.”

No case was filed till filing of this report as of 8:45pm.