Jail guards rang sirens at around noon as a practice, KDJ officials said. However, unconfirmed sources claimed the authorities raised it fearing uprising inside jail premises.

With increased police deployment, security measures in and around the jail were heightened since the alarm was raised, sources said.

Apart from notorious criminal Ershad Sikder and his accomplices, there are over 200 inmates serving various terms in the jail.

According to another jail official, the Khulna-based criminal is yet in the dark about his capital punishment due on May 10 midnight.

Appellate Division of the Supreme Court announced death penalty to the infamous criminal for killing Jubo League leader Khalid Hossain on May 16 in 1999. President Iajuddin Ahmed also turned down his mercy petition.