A 38-year-old man from the area has been arrested in connection with this incident and he remains in police custody.
The 15 and 20 year old girls were in Sainsbury’s on Guildford Road last Thursday between 1pm and 2pm when it happened.
Police are keen to speak with a male member of the public that intervened and asked the suspect to leave the store.
Any witnesses should contact police on 101.