Police received a report around 8.30pm that a woman was found collapsed within a unit of flats on Dromore Street. It was later confirmed that the woman had died.
A post-mortem examination will take place to determine the cause of death.
Three men - two aged 26 and one aged 30 - were arrested on suspicion of manslaughter and remain in custody. Enquiries continue.
Appealing for information, Detective Sergeant Ritchie said: “We would ask if anyone was in the wider Dromore Street area last night and noticed anything suspicious at this address or in the wider area to contact us on 101 quoting reference 1626 02/12/21 or Crimestoppers anonymously on 0800 555 111 or online at www.crimestoppers-uk.org”