UTV News is reporting that Army bomb experts are being sent to the scene of the small explosion in Belfast Cathedral quarter.
There are reports that restaurants and other premises in the area are being evacuated.
More top news
Clear skies allowed a satellite image to be taken, showing snow in the Pennines, north Midlands, Northern Ireland and Scotland yesterday.
Molly Smith, 5, won £500 after her accidental selfie with a snowman caught the attention of competition judges.
Harry Street, formerly Barry Williams, shot dead five people in a spree across the West Midlands in 1978.