Pro-hartal activists set off seven crude bombs in front of the Judge Court in the old part of the capital around 3:30pm.
Kotwali police station Officer-in-charge Shah Alam told the Dhaka Tribune that additional security forces have been deployed in the area after the incident.
Police are trying to detain those who blasted the crude bombs, said the OC.
Md Zahidul, sub-inspector of Kotwali police station said none was injured in the incident.
Badal Mia, a street vendor, who witnessed the blast, said some unidentified miscreants threw a number of crude bombs from upstairs of Dhaka District and Session Judge Court building at the vehicles perking area.
He said a bomb was also exploded on the rooftop of the three-storey office building of the Superintendent of police situated beside there.