Jail authorities said unknown criminals hurled the bombs over the boundary wall adjacent to the Makkushah Mazar on west side of the Dhaka Central Jail at about 10:30pm.

Assistant Inspector General of Prisons Abdul Mannan, who is Senior Superintendent in-charge of the Dhaka Central Jail, admitted the incident and said it did not cause any injury to inmates.

Earlier on March 22, the jail authorities stand-released six jail guards including the chief jail warden for beating up inmates in violation of the jail codes following sporadic clashes between two groups of prisoners.

A group of inmates led by 'Kangali' Zakir, a convict in Police Sergeant Ahad murder case, on Monday morning assaulted its rival group headed by Emran, an associate of dreaded criminal 'Sweden' Aslam, allegedly in a bid to establish control over drug trading inside the jail.

Following the incident on March 24 the home ministry formed an enquiry committee headed by deputy secretary (Administration) of the ministry and asked the committee to submit its report in a week.

A jail source said that violent incidents are taking place inside the Dhaka Central Jail as chain of command has broken down following appointment of some inefficient and controversial people, including even those suspended for negligence to duty, at top posts of the jail.