Lives are being put at risk by a spate of deliberate fires at a derelict building in Londonderry, a fire service group commander has warned.
Fire crews were called to the former St Mary's Youth Club building in Creggan five times between Saturday and Monday.
Three of the call outs were to fires that had been set deliberately, the fire service said.
The biggest fire destroyed 80% of the building as more than 40 fire-fighters battled a blaze on Saturday night.
Northern Ireland Fire and Rescue Service group commander Fergal Leonard said the public needed to be aware of the dangers of deliberate fire setting.
"NIFRS is appealing to people to stay away from the site and is warning about the dangers of deliberate fire setting," Mr Leonard said,
"Deliberate fires are a risk to both the public and firefighters and they could have an impact on the local community- if NIFRS resources are responding to a deliberate fire this may have the potential to cause a delay in response to a real emergency in the area."
Demolition work has been ongoing at the former youth club building ahead of the construction of a new multi million pound facility.
In a social media post on Tuesday evening, St Mary's Youth Club said the site contractor has agreed to employ security staff to the site.