Police have ramped up patrols after attacks and attempted robberies on schoolchildren.
A letter from Barton Court Grammar School in Canterbury warned parents of recent incidents involving pupils being targeted in the city centre.
Last week, a youngster was punched after a gang approached him while another pupil was attacked the following day.
The force says it has placed extra officers on patrol in the city centre when secondary schools finish.
In a letter sent to parents on Thursday, acting deputy headteacher Mrs Smith wrote: “I would like to draw your attention to incidents the school is aware of, regarding student safety in and around Canterbury city centre.
“Most recently, Barton Court students have been the victims of attempted robberies or physical assaults.
“We are aware of incidents occurring in and around Dane John Gardens, the top of Canterbury High Street near WHSmith / Poundland, Sainsbury’s and the bus station.
“With this in mind, I would ask you to discuss with your son or daughter personal safety.
“Report anything suspicious they see. Call 999 if they feel in any danger, or see anything that requires immediate police action.
“If they are close to school, they should return to the school office to seek help.”
The school has not responded to KentOnline’s request for further comment about the incidents.
Police confirmed officers have been alerted to two recent incidents involving schoolchildren in Canterbury.
The first took place in the Dane John Gardens at about 4.30pm on Wednesday when a 13-year-old boy was reportedly approached by a group of teenagers, one of whom punched him.
The second took place at an undisclosed location in the city on Thursday morning when a 14-year-old boy was reportedly assaulted.
Neither child sustained serious injuries.
Inspector Paul Stoner, of Canterbury Community Safety Unit, said: “It is important children feel safe when travelling to and from school and a member of our Child Centred Policing Team is in contact with these pupils’ school following these incidents.
“We have recently placed extra officers from our Neighbourhood Task Force and Beat Team on patrol in the city centre at the times when secondary schools finish.
“I would urge young people to think about the impact of their actions on others, and I ask parents to speak to their children about what they are doing after school and the consequences that committing offences now may have on their futures.”
He adds police urge parents and children to report offences as soon as possible after they happen or call 999 if a crime is in progress.