Dhaka, March 8 -- Authorities have arrested at least 36 members of the banned Islamist organisation Hizb ut-Tahrir since Friday, according to the Chief Advisor's Office, or CAO.

Among those detained is Saiful Islam, one of the group's key organisers, the CAO said in a statement on Saturday.

Hizb ut-Tahrir was outlawed in 2009 for alleged anti-state activities.

Police have launched a nationwide crackdown to apprehend members of the outfit who participated in an unauthorised gathering outside Dhaka's Baitul Mukarram Mosque on Friday.

"We are analysing video footage of the rally. We have identified many members of Hizb ut-Tahrir and they will be arrested for joining a political programme organised by a banned organisation," said Inspecto...