DETECTIVES are today stepping up the hunt for an arsonist who torched a house containing African asylum seekers.

Police say they are "following several lines of inquiry" for the firebug behind the attack in Southampton.

Ten men had a lucky escape after an arsonist broke into the multi-occupancy property in Carlton Road, near Bedford Place, as they slept.

In a chilling twist, the intruder removed a smoke alarm from the ceiling of a landing before setting fire to an adjacent room.

Detectives said it was only luck that one man sleeping just yards away woke up, smelt smoke and raised the alarm.

Police said the blaze is being treated as racially motivated.

Det Insp Paul Barton, leading the inquiry, said: "This was an extremely serious incident in which all ten occupants could so easily have died. What is particularly sinister is that the offender actually broke into the premises and removed the smoke alarm before starting the fire, so clearly did not intend the occupants to wake up."

About a dozen firefighters from St Mary's received a 999 call just before 3.15am on Friday.

All ten occupants were led to safety before crews wearing breathing apparatus tackled the blaze, which severely damaged the property.

One man needed treatment at Southampton General Hospital for the effects of smoke inhalation.

Hampshire Fire and Rescue Service and Southampton police launched a joint investigation to pinpoint the cause of the blaze.

It was thought inquiries were centring on a red petrol can found abandoned at the scene.

Police also believe the arsonist was likely to have suffered burns during the incident, and are keen to hear from anyone who knows of someone with an unexplained burn injury.

Detectives were carrying out house to house inquiries in the area while scenes of crimes officers performed forensic tests inside the property.

All ten asylum seekers were re-homed in alternative accommodation after the blaze.

Each had been living in their own single room in the privately-owned property.

It was thought all had come to Southampton seeking refuge from countries in Africa, including Somalia.

Iain Girvan, who lives opposite the property in Carlton Road, described how he had been woken, saying: "I thought I could hear a fire alarm going off. I woke up and looked out of the window and saw fire trucks drawing up, and went out and had a look. As far as we were aware, nobody was injured. By the time I looked out, the emergency services were there.

"People were standing outside but there wasn't any obvious smoke or flames."

The attack has also been universally condemned across Southampton.

The Rev Ian Johnson, rector of Southampton city centre's parish, who has been liasing with Muslim community leaders about the attack, said: "The fact that someone has even gone to the trouble of removing the smoke alarm is appalling.

"This has never happened in Southampton before - and we pray God nothing like this ever happens again."

Southampton Itchen MP John Denham said: "I condemn any dangerous and irresponsible action which could put lives at risk."

Adrian Vinson, leader of Southampton City Council, said: "I am appalled that anyone in our city could be responsible for such a cowardly attack on vulnerable people."

A City Council spokesman said there were currently up to 500 asylum seekers living in the city.

All were accommodated in private rented houses, arranged by the council on behalf of the Home Office.

Information to Hampshire police on 0845 045 4545, or the anonymous Crimestoppers line on 0800 555 111.