According to Dahun, the video was sent to the management of the school by a concerned parent who declined to specify when the incident took place and the person involved.
The Director added that preliminary investigation revealed that the incident took place two sessions ago and was handled administratively.
He said: “For the avoidance of doubt, further investigation is ongoing on the matter and parents are advised to avoid recycling these sorts of materials to create tension and ill feelings.
“The service is committed to providing top class education in its schools under a conducive atmosphere.
“The NN is also not unmindful of the need to uphold standards and discipline in its schools without recourse to unorthodox method of achieving these goals.”