Detectives are investigating after a 16-year-old girl in school uniform was sexually assaulted in Poplar Place on Wednesday.
The next day a 17-year-old girl was followed off the 422 bus and attacked in Wellington Street.
In a letter home to concerned parents, Safer Schools Sergeant Geoff Warren said: “Enquiries have led us to believe the same suspect committed both sexual assaults.
“Although I do not wish to cause alarm to anyone I feel it is important for parents, guardians and children to be aware of these incidents and take reasonable measures to ensure our children are safe.”
He advised schoolchildren to keep to busy well-lit areas “where possible” and call 999 immediately if they feel uncomfortable.