Postal staff have escaped injury after a packet containing a firework exploded in a Northern Ireland mail sorting office.

The complex at Royal Mail House in Tomb Street, Belfast, was evacuated after the blast sparked a security alert at around 11am on Friday.

Army bomb experts and emergency services were called to the scene to inspect the premises.

The small explosion took place in a returns centre which handles mail from across Northern Ireland and Britain.

It is understood the blast happened while a member of staff was handling the package, but the employee was not injured.

A spokesperson for Royal Mail said: "We can confirm that Royal Mail House in Tomb Street, Belfast was briefly evacuated at 11.00am this morning after a small packet containing a firework went off in the National Returns Centre.

"Police and fire and rescue services were called to the scene. No staff were injured and there was no disruption to service."