A prisoner allegedly hit the jailor of Sylhet Central Jail with shackles yesterday morning.
With injuries to the head, Md Masud Parvez Moin was taken to Sylhet MAG Osmani Medical College Hospital.
Promod Chandra Das, a lifer convicted of murder, attacked Masud from behind with the shackles used for another prisoner that kept in the jail as the inmate was scheduled to be produced before a court, said Md Sogir Miah, senior jail superintendent.
The jailor was checking the list of the prisoners at his desk near the jail's main gate, he said.
The attacker was taken to the secured custody with the prison security being increased, he added.
Deputy Jailor Nur Mohammad filed a case with Kotwali Police Station against the attacker.
Sogir said the cause behind the attack could not be ascertained immediately.