A woman walking her dog was shoved to the ground during an attack by two female muggers.
The victim, a Leeds woman in her 50s, was set upon near the Raj restaurant in the Bootham area of York at about 8pm on Friday.
Her attackers demanded money and pushed her to the ground before fleeing empty handed after a male passer-by aged about 25 shouted at them to stop.
The woman was left “very shocked and shaken” by the incident, said police.
The suspects are described as white, in their late 20s and with dyed blonde hair.
One of the women was in a short-sleeved white top while the other was wearing a blue top and carrying a handbag.
North Yorkshire Police’s Acting Det Sgt Matt Wilkinson said: “This was a disgraceful attack on a woman out walking her dog.
“I am appealing to anyone who witnessed what happened, in particular the young man who we believe disturbed the pair.
“I would also like to hear from anyone who can help us identify the suspects.
“Perhaps you know who they are or have heard them discussing the incident.
“If you can help us find those responsible, please contact us as soon as possible.”
Anyone with information about the incident is asked to get in touch with North Yorkshire Police’s York serious crime team using the force’s 101 phone number.