Knife-wielding man threatens SA teen

A man who threatened a teenaged girl with a knife in Adelaide may be a serial offender, police believe.

A man being sought over a series of attacks on women in Adelaide has apparently struck again.

A 16-year-old girl escaped without harm after she was threatened by a man with a knife while walking in Melrose Park on Monday afternoon.

Police believe the man was also responsible for a series of assaults on Sunday morning.

The suspect hit a 53-year-old walking in the city's southeast less than an hour after he brandished a knife at a 33-year-old in a nearby suburb.

He also tried to grab a 22-year-old, and followed a 61-year-old in a car and on foot.

A composite image of the suspect and CCTV footage of his car have been released.

Pedestrians have been urged to walk in pairs and stick to well-populated areas if they feel unsafe.