A number of vehicles were damaged during Wednesday’s attacks, leaving at least five people injured in the Court Point area.
Nizami led the notorious Al-Badr, which spearheaded the killing of intellectuals just before the end of the Liberation War.
Witnesses said Jamaat-Shibir activists took out a flash procession at the city’s Bandarbazar shortly after Nizami’s conviction and threw stones at the police.
Police fired several shots in the air before retreating.
The Jamaat-Shibir activists then attacked the Awami League activists as they were preparing to take out a victory procession at Court Point.
Awami League activists chased the attackers after a large contingent of police arrived at the scene.
The running battle created panic among the locals, many of whom were seen running for shelter and businessmen downing shutters.
Sylhet Metropolitan Police’s Additional Deputy Commissioner Rahmat Ullah later said the situation was under control.