The police have detained 54 people in Gazipur on allegation of attacking the vehicle carrying Hasnat Abdullah, National Citizen Party (NCP) chief organiser in the southern region.
The police claim that almost all of them are leaders and activists of the Awami League and its affiliated organisations.
The arrests were made on Sunday night.
Miscreants attacked a vehicle carrying Hasnat Abdullah, chief coordinator (South) of NCP, at the Chandana intersection in Gazipur on Sunday around 7 pm where Hasnat sustained minor injuries.
Leaders and activists of National Citizen Party (NCP) and Anti-Discrimination Student Movement staged demonstrations across the country, including the capital Dhaka, protesting last night's attack on Hasnat Abdullah.
NCP leaders at the scene called for the attackers to be brought to justice within 24 hours, urging the authorities to take immediate legal action.