The students, who had assembled outside the Old Secretariat in Shaheed Gunj area, alleged that they were deliberately failed in the examination, official sources said.
Demanding that the exam should be reconducted, they tried to break through the security barricade, but were stopped by the police which resorted to cane charge to disperse them, they said.
Two protesters were injured in police action while four others were detained, they said, adding that one journalist covering the protest was also detained, but was released later.