A man apparently trying to lure schoolchildren into his car may have approached nine pupils in the past week, according to police reports.
Officers are investigating multiple incidents of a driver offering children a lift or trying to talk to them in Southampton and Eastleigh.
Nine incidents have been reported in Hamble-Le-Rice, Hedge End, Bursledon and Southampton since 17 November.
Some schools sent warning letters to parents after pupils were approached.
Officers said boys and girls had been targeted and had reported it to their parents or school.
No children have got into a vehicle or have been hurt.
Hampshire Constabulary, which is carrying out patrols in the area, said "suspicious incidents" had been reported at:
- Newtown Road, Southampton,
- Satchell Lane, Hamble-Le-Rice
- Wildern Lane, Hedge End
- Lower Northam Road, Hedge End
- Hamble Lane, Bursledon
- Ashley Crescent, Southampton
- Sholing Road, Southampton
- Middle Road, Southampton
- Wakefield Road, Southampton
A spokesman said: "We know there maybe similar reports of suspicious incidents that have occurred in other areas of Southampton.
"We continue to regularly review all similar incidents to identify patterns as part of the ongoing investigation process."
Hamble School said a man driving a grey/silver Vauxhall car offered to take a boy home on 17 November, claiming he knew his mother.
Described as white, aged 50-60, with short, grey hair, he drove off when the boy asked him for his mother's surname.
A letter to parents said there had also been reports from other schools and an incident in Woolston in a shop "potentially involving the same individual".
Regents Park Community College in Shirley posted a warning on its website following two incidents.
The school said they happened at Southampton Common, near the Bellemoor public house, and in Shirley precinct "where a male was seen trying to encourage a 12-year-old into his vehicle".