Derby City Council has restricted access to its headquarters after staff received ‘malicious communications’ over the phone.
The local authority reported the threats to the police at about midday on Monday (9 December), while security staff at its Council House temporarily locked the doors.
The council headquarters is now operating on an appointment-only basis.
A spokesperson for Derby City Council said: ‘The safety of our staff and residents is our top priority and we take threats of this nature very seriously.’
The council is working with Derbyshire Police as enquiries continue.
