Security has been beefed up in Brahmanbaria following the arrest of Hefazat-e-Islam Joint Secretary General Mamunul Haque.
Additional police personnel have been deployed at various points in the district town since noon.
They, alongside RAB members, were seen patrolling the main roads of the district town from 3 pm on Sunday.
However, according to the police, the patrolling was part of the routine exercise in the lockdown.
Brahmanbaria Additional Superintendent of Police (Sadar Circle) Mozammel Hossain Reza said, "The deployment of our police members is part of the ongoing activities to keep the law and order situation normal during the lockdown".
He warned that any attempts to cause unpleasant incidents will be suppressed.
Earlier on April 9, LMG posts were set up in all police stations, outposts, camps and investigation centres, including the office of the Superintendent of Police, in the district.
Till Sunday, police have arrested 298 people, including many Hefazat activists, in 55 cases lodged over the mayhem that took place on 26-28 March.
On 27 March, at least five people were killed and around 50 others, including 25 cops, injured in clashes between members of law enforcement agencies and locals during Hefazat's demonstrations at Nandanpur in Sadar upazila.
They had staged the protests against Indian Prime Minister Narendra Modi's visit to Bangladesh.
The next day, during Hefazat's countrywide dawn-to-dusk hartal protesting police action on their anti-Modi processions in Dhaka, Chattogram, and other districts, activists set fire to three buildings, including the land office in Brahmanbaria Sadar upazila.
They had also attacked a Chattogram-bound train at Talshohor Rail Station in Brahmanbaria town.
Besides, the Hefazat supporters also vandalised several private and government establishments, including the Zila Parishad building, municipality building, Police Lines, Industrial School, land office, Alauddin Music Academy, and Foirtala Bus Stand in Sadar upazila.
The supporters had also attacked Brahmanbaria Press Club and confined some journalists to the premises.