An 87-year-old woman was punched in the face during a row with two teenage girls on a bus.
The elderly victim was left with a black eye after allegedly being attacked by one of two teenagers who had boarded the Route 166 bus in Croydon, south London without paying.
Police have now released CCTV footage of the "nasty" attack in a bid to track down the girls.
The incident took place on Brighton Road in Coulsdon at around 3.20pm on Friday October 16.
Most of the passengers had left the bus after the girls started to argue with the driver about their fare-dodging.
Another female passenger came to the aid of the victim, who was taken to St Helier Hospital and discharged later the same day.
The suspects - who fled the scene - are described as:
aged between 14 and 18 years old
One of the girls was also wearing a black headband.
"This was a nasty attack on an elderly woman who just wanted to get home," police sergeant Arran Hillier said.
"I urge anyone who may recognise the suspects to contact the police."