Alumni of Bangladesh University of Engineering and Technology take part in a protest in Dhaka on Wednesday. Agence France-Presse
Demonstrators gathered in major cities under the slogan "defending the peace" to denounce the deaths. 462 campaigners have been killed since 2016, according to the country's ombudsman.
The "Justice First" marches were called by the Sudanese Professionals' Association, which has been spearheading the protests since December.
Bangladesh police were set to file charges on Wednesday against 16 people, including the headmaster of an Islamic seminary, over the shocking murder of a 19-year-old girl burned to death.
The US Treasury accused Mudalal Khoury in 2015 of "an attempted procurement of ammonium nitrate in late 2013". It sanctioned his brother Imad a year later for engaging in business activities with Mudalal.
The closure is set to be effective from 6 p.m. (1400 GMT) on Monday, it is in line with the country’s effort to curb the spread of coronavirus.
Co-Win, the coordinating app was developed by the Indian government to help healthcare workers manage and monitor the immunisation programme.