Clashes have broken out between refugees from Sri Lanka and Afghanistan at an Australian immigration detention centre on Christmas Island. Officials took more than half an hour to break up the fights between about 150 inmates, 40 of whom were injured in the clashes. The centre has been struggling to cope with a recent influx of refugees, many arriving by boat from Sri Lanka. Fighting erupted in the men's section of the centre, with Afghan and Sri Lankan refugees using tree branches, pool cues and broom handles to attack each other. Three people were taken by plane to Perth for treatment for broken bones. Another 37 people were given medical treatment on the island. Immigration authorities on Christmas Island are investigating the cause of violence, and Afghan and Sri Lankan inmates have been temporarily segregated as a precaution.