Officers were called to Hill Street off London Road at around 12.40pm on Friday to reports a man driving a moped fired a gun towards two men.
The three men left on foot but a 24-year-old man has been arrested by officers and remains in police custody.
Officers cordoned off Hill Street from the junction with London Road up to the Ozmen supermarket and Denby Street close by.
A police helicopter was also deployed.
Detectives were seen making door to door enquiries at the Sheldon apartments in the middle of the cordon.
The Star understands passers-by found some discarded ammunition while another witness who didn't wished to be named heard the shots from a nearby takeaway.
Police say the men were thought to be involved in an altercation before the shots were fired.
Superintendent Colin McFarlane said: "The exact circumstances around the incident have not yet been ascertained, but it is believed there was then an altercation between the two men and the man on the moped, which resulted in all three of the men leaving the scene on foot. No injuries have been reported at this time.
“The investigation is in the very early stages and a section of London Road has been cordoned off while officers begin initial enquires at the scene of the incident.
“A 24-year-old man has been arrested on suspicion of firearms offences and remains in police custody at this time.
“There will be an increased police presence in the area throughout the rest of the afternoon and over the coming days to offer reassurance to the local community.”
Anyone with any information is being urged to call police on 101, or Crimestoppers anonymously on 0800 555111, quoting incident number 384 of March 30, 2018