A locking assembly is provided for securing a rod in a rod receiving channel of a polyaxial bone anchoring device for use in spinal or trauma surgery, said locking assembly comprising a first locking element (9) having a first end (91) and a second end (92), a longitudinal axis of rotation (C) and an outer surface portion with an external thread (93), a coaxial bore passing through said first locking element, an internal thread (94) provided at a portion of said bore, and an engagement portion (95, 96) for a driver to rotate the first locking element, a second locking element (10) having a first end (101) oriented towards the first end (91) of the first locking element, and an opposite second end (102), an outer surface portion with an external thread (103a) cooperating with the internal thread (93) of the first locking element and a portion (105) that prevents the second locking element from rotating when inserted into the rod receiving channel (12) of the bone anchoring device, wherein when the first locking element (9) is rotated to move in a first axial direction the second locking element (10) is configured to move relative to the first locking element (9) in an opposite axial direction.
