Forty Ansar personnel, held by Bangladesh Army from the Secretariat following a clash with students on Sunday night, were handed over to police.
AKM Shahabuddin Shaheen, officer-in-charge of Shahbagh Police Station, said the army handed over the Ansar members to them on Sunday night.
A case will be filed against the detained Ansar members, he said.
On Sunday noon, Ansar personnel blocked all five gates of the Secretariat, demanding the nationalization of their positions.
The Ansar members took position in front of the Secretariat and its various gates, effectively sealing off the administration hub.
The Ansar battalion called off their protest and returned to work following discussions with Home Affairs Adviser Lt Gen (retd) Md Jahangir Alam.
Around 9 pm, a clash erupted between Dhaka University students and Ansar members at the Secretariat as news spread that key figures from the Anti-Discrimination Student Movement including Sarjis Alam and Hasnat Abdullah were confined in the Secretariat.
Students from several halls of Dhaka University gathered at the Raju Bhashkorjo on campus. They marched towards the Secretariat area, resulting in a clash between students and Ansar members that left several injured.