A London tower block fire that left six people dead, including a three-week-old baby and two children, was being treated as suspicious by police last night.

About 30 people were rescued from the fire at the 12-storey Lakanal House on the Sceaux Gardens Estate, Camberwell. More than 100 firefighters tackled the blaze, which started in a flat on the fourth floor at 4.20pm on Friday. Speaking at the scene, chief superintendent Wayne Chance, of the Met Police, said the fire spread rapidly to the 11th floor.

The bodies of a six-year-old child and two adults were found at the scene. The three-week-old baby, a seven-year-old child and a woman were later pronounced dead in hospital. A firefighter remains in hospital and is being treated for minor injuries.

A London Fire Brigade (LFB) spokesman said preliminary investigations have been carried out at the scene by two specialist teams. "They will be working alongside our firefighting crews," he said. But it will take "weeks if not months" to establish how the blaze in southeast London happened.

In addition to the 30 people who were rescued, 120 people were evacuated from the building. Those who were forced to leave their homes were taken to an emergency centre, set up by Southwark council in nearby Welton Hall.

Carol Hunter, who lives in a building that backs on to Lakanal House, said: "It was horrible. We saw lots of children banging on the windows to get out and families screaming."

Firefighter Paul Glenny, who tackled the blaze, said: "I've been in the job for 30 years, and I've never seen anything like it.

"The hot weather and the fact that people's windows were open made the fire what it was."