Army technical officers in Talbot Street, Belfast on Friday night after small bomb explosion

THE PSNI has on Friday night issued advice to shop, bar and restaurant owners to carry out a thorough check of their premises before leaving.

It follows the partial explosion of a device left in a rucksack at St Anne’s Square off Donegall Street in Belfast city centre.

Police say they still do not know what type of device has exploded which forced hundreds of Christmas revellers to quit their parties in the area.

People living in apartments were also evacuated and have been welcomed into Belfast City Hall for shelter.

However, the PSNI say it is important all keyholders check their premises in case devices have been left.

There is a fear dissident republicans may switch tactics again and start a firebombing campaign at the height of the Christmas shopping rush.