Police in Strabane investigating an incident in the town centre on Friday night are appealing for witnesses and information.
It has been reported that a 17-year-old female was assaulted in a grassy area of the town centre, known locally as 'The Meadows'.
As part of enquiries, a 17-year-old female and an 18-year-old male were arrested on suspicion of offences.
They have both since been released on bail, pending further enquiries.
Investigations continue as police work to establish exactly what happened and who was involved.
In particular, they want to hear from anyone who was in Strabane town centre on Friday night, between 10:45pm and 11:15pm and who witnessed what happened to contact them.
Police are aware that footage of the incident may be circulating on social media.
They say the sharing of such footage is likely to cause additional distress and they would ask people not to do so.
Anyone with information is asked to contact police directly on 101.