A man was injured in the face when he was hit by a tool, possibly a hammer, in an argument involving some workers.
He was taken to hospital for treatment though the extent of the injuries are still unknown.
The incident occurred at about 1.30pm. at Blata l-Bajda Girls Secondary School where refurbishment works are in progress.
The school forms part of San Gorg Preca College.
The victim is believed to have indicated his aggressor to the police who are now speaking to the suspect.