Northern Territory Police are investigating after an alleged attempted sexual assault in Darwin overnight.

Around 12:30am, police CCTV operators detected a female, aged from 16 to 18,  being assaulted by an 18-year-old man in Karama.

Another man intervenes and confronts the offender with an edged weapon before chasing him from the scene.

He was then joined by several other men who allegedly assault the offender.

The 18-year-old received multiple lacerations and bruising and was conveyed to Royal Darwin Hospital for treatment.

He currently remains in police custody.

The young woman was also conveyed to Royal Darwin Hospital for assessment.

Detectives from the Sex Crimes Division are investigating the incident and are urging anyone with information, or dash-cam footage, to make contact on 131 444. Please quote reference P24131578.

Anonymous reports can also be made through Crime Stoppers on 1800 333 000 or through https://crimestoppers.com.au.