Two men have been released from police custody following a fire at a former customs building in Newry, County Down.
The men, aged 19 and 53, had been arrested on suspicion of arson shortly after crews were called to the scene at about 01:00 BST on Saturday.
They have been released on police bail pending further inquiries.
Forty firefighters worked through the night to bring the blaze at Carnbane Industrial Estate, on Shepherds Way, under control.
They found a "well-developed fire" at the former HM Revenue and Customs clearance station.
The building was empty when the fire started and there were no reports of any injuries.
However, part of the roof has collapsed and substantial damage has been caused to the interior.
The Northern Ireland Fire and Rescue Service (NIFRS) deployed five fire engines and an aerial ladder platform to tackle the blaze.
Alan O'Neill from NIFRS told BBC News NI the first crew arrived at the scene within three minutes.
SDLP councillor Michael Savage said local residents raised the alarm after hearing a "loud bang".
"Local fire crews are to be commended for their swift response in dealing with this major blaze and their bravery in tackling this serious fire," he said.
"The Newry crews were on the scene within three minutes."
The councillor added: "I am just thankful that no one was hurt."
No houses were evacuated during the operation, according to NIFRS.
In recent years, plans have been submitted to develop the former HMRC site into a retail park with a coffee shop and restaurant units.