The arrestees are Ahmed Ali, 57, his wife Salma Ahmed, 50, their son Jakaria, 35, and Kibria, 30 and daughter Asma Ferdous Dipa, 25.
Tipped off, a special team of ATU conducted a drive at a flat located on the 3rd floor of a 5-storey building at Rupnagar Residential area around 1:30 am, said Mahiduzzaman, superintendent of police (SP) at the ATU Headquarters (Media and PR).
He said police knocked on the main door of the house repeatedly but no one opened it. At one stage, they (militant suspects) opened it and swooped on the police with a sharp weapon, leaving three cops injured, the SP added.
He said Jakaria was shot and injured as police fired gunshots in self-defence.
Jakaria, an active member of the banned outfit Ansar Al Islam, was admitted to Dhaka Medical College Hospital while the three injured cops to Rajarbagh Police Lines Hospital, he added.
He further said alleged militant Ahmed Ali is a senior principal officer of Sonali Bank Local office of Motijheel.
Though Ali has been living in the flat with his family members for last ten years, they used to live an isolated life there, the SP Mahiduzzaman said, adding that suspicious people used to visit the flat as well as holding secret meetings regularly there.
Some explosive substances, improvised devices and some books on extremism were recovered from the house, said SP Mahiduzzaman.