Staffordshire firefighters spent over 20 hours dealing with two fires in Longton over the weekend.
"Following a joint fire and police investigation this morning we are treating this fire as suspicious and the police have made some arrests in connection with this incident."
Group Manager, Brian Griffiths
In the early hours of Saturday morning they were called to an unused shop on Market Street in Longton where there was a fire on the second floor.
Firefighters from Longton, Hanley and Cheadle plus the aerial ladder platform from Longton tackled the fire using main and hose reel jets.
Once the fire was extinguished a fire investigation was due to commence however due to the damage caused by the blaze, fire investigation personnel were unable to carry out a full investigation.
Group Manager, Brian Griffiths said: "We have been unable to carry out a full fire investigation and have therefore had to record the cause as unknown. We have no reason to treat the fire as suspicious however due to the structural instability we’re unable to investigate further."
The incident was closed at 5pm on Saturday.
At 3.47pm on Sunday, crews from Longton, Hanley, Stone and Ipstones, again including the aerial ladder platform from Longton were called to a warehouse on Caroline Street in Longton.
Fire Control received 16 repeat calls reporting the fire as billowing smoke could be seen in surrounding areas.
Firefighters used three main jets to tackle the fire and several local roads had to be closed whilst the blaze was dealt with. Smoke began to drift over the railway so trains were also temporarily halted whilst firefighters battled to make the area safe.
Group Manager, Brian Griffiths said: "This was a very severe fire and has destroyed the contents of the building, believed to have mainly been pottery lithographs. Following a joint fire and police investigation this morning we are treating this fire as suspicious and the police have made some arrests in connection with this incident."