Police have released e-fit images of two men they want to trace after two robberies in Leeds.
An 18-year-old man was walking along North Hill Road, Headingley, at around 9.30pm on March 20 when he was approached by the suspects.
They threatened him with what was believed to be a knuckle duster, demanded he hand over his mobile phone and then escaped on foot.
The same suspects are then believed to have approached a woman in her 20s on North Hill Road a short time later.
They demanded that the woman hand over her mobile phone.
It is believed a third woman was approached by the suspects at around the same time.
Police are asking her to get in touch as they believe she may have information valuable to the investigation.
Officers also want to hear from anyone who recognises the men pictured or has any other information on the robberies.
Contact PC 3181 Wherrett at Leeds District CID on 101, quoting crime reference 13170128229.
Information can also be passed anonymously to independent charity Crimestoppers on 0800 555111.