Shortly after midnight a report was received by police that a small explosion had been heard following a sighting of a man, dressed all in black, setting an object alight in the Chichester Street/Victoria Street area.
The area was sealed off as police and ATO inspected the the object.
Following an examination of the object it was declared to be an aerosol can contained within a rucksack which had exploded causing no damage.
Cordons were lifted and roads re-opened shortly after 3am.
Officers are appealing for anyone who noticed a man dressed in black, carrying a rucksack or any other suspicious activity in the area.
Anyone with information is asked to contact CID in Musgrave on the non emergency number 101.
Information can also be passed anonymously through the independent charity Crimestoppers on 0800 555 111.