FIRE investigators and police are looking into blazes which damaged two disused business premises over the weekend.

One of the buildings, the former Swandene Timber Merchants, in Seaham, County Durham, was left in an unsafe condition following the fire on Saturday.

Most of the roof at the derelict furniture production warehouse collapsed as a result of the intense heat and flames.

It was well alight when fire crews reached the scene, in Church Street, shortly after 8pm.

Station manager Andrew Allison, of Durham Fire and Rescue Service, said: "At its height, there were seven fire appliances and an aerial ladder platform tackling the fire, involving crews from Seaham, Peterlee, Durham and Wheatley Hill.

"Because the building was considered unsafe, it was fought from outside. No one was inside.

"There was a worry that it might spread to a nearby disused cinema, but, fortunately, the wind was in our favour.

"It wasn't until 1.30am that the final fire crew left and it was being fenced off, with a warning issued for people to keep away.

"The cause is unknown and police are investigating," said station manager Allison.

Earlier on Saturday, four fire crews were called to a blaze at the former Mono Containers premises, on the Dragonville Industrial Estate, Durham.

Mr Allison said although boarded up, there were signs it had been entered on a number of occasions.

"For that reason, we are assuming it was a malicious act, although I understand it was due to be demolished anyway.

"It was heavily smoke-logged when we got there, but the fire was limited to two small rooms.

"Crews went in wearing breathing apparatus to carry out a search to check no one was inside."

Mr Allison added that both blazes highlighted the dangers posed by people entering disused buildings.