At least 30 people were injured, 12 by bullet, during a clash between BNP-Jamaat-e-Islami supporters and police-Border Guard Bangladesh (BGB) personnel in Torabar area under Hajiganj upazila in the district on Monday evening.
Hajiganj police station Officer-in-Charge Shah Alam said: "The situation is under control now."
Witnesses said BNP-Jamaat activists vandalised 10 vehicles in different areas during their sit-in programme on Monday.
OC Shah Alam said police went to the spot hearing the news of torching a motorcycle of a journalist. BNP-Jamaat activists confined the law enforcers there.
Later, extra forces of police and BGB from Chandpur rushed in and took the situation under control.
Police lobbed 42 rounds of bullets and tear shells to calm the situation.