Police arrested four suspected members of banned militant outfit Hizb ut-Tahrir Bangladesh in the city's Adabar area in separate drives during the last five days.
They also seized a huge number of leaflets containing anti-government statements, posters and books from their possession.
Inspector Ataur Rahman of Adabar Police Station told The Daily Star that following a tip-off they arrested Ibne Mizan Sentu, 22, an honours student of Mohammadpur Central University College, on February 23.
Following statements by Mizan in a three-day police remand, the law enforcers arrested three others in two separate drives on Saturday night and yesterday, the official said.
The three students are Ahmed Hossain, 21, of Ahsanullah University of Science and Technology; Mushfiqul Islam Lincon, 21, of American International University of Bangladesh; and Fakhrul Hasan Jiban, of University of Asia Pacific.
During preliminary investigation, they admitted to be active members of the outlawed group, said the inspector, adding that police are trying to arrest their leaders, named by the arrestees during interrogation.