Ulster Unionist councillor Darren Guy believes the incident was specifically timed to cause as much disruption as possible and that the alert may have been linked to an event previously held at the hotel.

"Recently, there was a careers event held in that hotel where I believe an RAF [Royal Air Force] stall was there for the careers event at that time.

"I think this was specifically done this week to cause as much disruption as possible during the 40th Halloween celebrations with thousands of international visitors visiting the city and the amount of families, especially young families going out to enjoy the many things on offer.

"It is totally reckless and these people don't think about anyone else but themselves."

Sinn Féin councillor Christopher Jackson said it was too early to "speculate" about any link between the alert and the jobs fair.

"We need clarification from those responsible," Jackson said.

He said this was "a disgusting attack on the city and the people of Derry".

"There is no justification whatsoever for carrying this out and putting people in danger, especially when the city is gearing up for the 40th anniversary of the Halloween festival.

"Derry is a warm and welcoming place and it's disgusting why someone or some organisation did this."

SDLP MLA Mark H Durkan told BBC Radio Foyle's North West Today programme police officers acted swiftly and that his thoughts were with them, the hotel staff and the hotel guests who were impacted.

"This is extremely traumatic for staff and those staying at the hotel," Durkan said.

"This should be a positive week for Derry, with all the events going on with Halloween in the city, there is a lot of buzz, but this has certainly painted a less positive picture of this city.

"This is not representative of Derry and the vast majority of people in this city, who would, like me, completely reject this."

Julie Middleton, Democratic Unionist Party (DUP) assembly member for Foyle, told BBC Radio Ulster's Good Morning Ulster programme on Wednesday that she was "deeply disturbed and disgusted".

"There is no excuse to leave a viable device anywhere at all, but in the middle of Ebrington Square, where you have people at their work, families out enjoying some half-term fun and tourists visiting and unfortunately this was designed to cause disruption and with any viable device, it was obviously designed to cause harm."

Middleton said many children would also be in the vicinity enjoying the fun fair.

"To think anyone would place something like this near our children, or anyone for that matter, is just deeply wrong."