An investigation has been launched after a fire was started in the lobby of a high rise block in Preston, say fire services.
Crews from Preston were called to Richmond House in Avenham Lane at around 8.30pm on Monday, March 5 after an automatic fire alarm sounded.
Two fire engines attended the scene and firefighters found discarded newspapers had been set alight in the main escape route for the block.
Firefighters have condemned the actions of the people who started the fire as "reckless" and "extremely dangerous" and are calling for residents to remain vigilant.
Watch Manager Mark Woodward said: "When we arrived at the block we found that newspapers had been deliberately lit in the ground floor flats.
"The actual fire had burnt out although there was still some smoke.
"This had activated the fire alarm although there was no need to evacuate residents.
"We asked the police to attend and the fire is being treated as suspicious.
"It is always a serious matter when somebody sets light to items in the means of escape from a high rise building.
"We are now investigating to see if we can find who did this.
"It is extremely dangerous and risky for anyone to set fire to combustible materials.
"We would ask residents and owners to not leave these items in a means of escape.
"If you see them then remove them or ask the property owner to remove them.
"We will be examining CCTV to see if we can identify the culprits."
Firefighters spent around 30 minutes at the scene.
A joint police and fire service investigation into the incident has been launched.