A viable postal device was delivered to a hotel in Ebrington Square, Londonderry, police have confirmed.

The incident triggered a security alert at around 3.20pm on Tuesday afternoon, causing the evacuation of the hotel and several neighbouring properties.

A Halloween fun fair was taking place in the area at the time.

Army ammunition technical officers attended the scene in the Waterside area of Derry and carried out a controlled explosion on the package.

The alert lasted until close to midnight, according to police.

Chief Superintendent Gillian Kearney, area commander for Derry City and Strabane, said the investigation is at an early stage and that one line of inquiry is that dissident republicans may be responsible.

She described the incident as reckless and targeted, and thanked the public for their patience.

Justice Minister Naomi Long condemned the attack, calling it shameful and noting the presence of families and young people celebrating Halloween.

Foyle Assembly member Julie Middleton said the incident was deeply disturbing and praised police for their work.

Police are appealing for anyone with information to come forward.

No arrests have been reported.