Police are investigating damage caused to three Murray Bridge schools.

Police are currently investigating incidents of damage to three Murray Bridge schools, which occurred over recent nights.

On Wednesday police discovered a glass door which had allegedly been smashed at the school on Lohmann Street after police responded to an alarm activated at the school at around 11:50am.

A pop riveter was allegedly thrown through a window causing it to smash on Florence Street, sometime on Wednesday night.

At around 6:45am yesterday, police were called to a school on North Terrace after alarms were activated.

Entry had allegedly been gained to one of the buildings and exterior glass panels had been broken.

Police ask anyone with information about these incidents to contact Crime Stoppers on 1800 333 000 or report online at www.crimestopperssa.com.au.