A man who tried to kill himself by cutting a gas line started a fire in a public housing estate apartment in Sheung Shui in the New Territories on Tuesday.

The 37-year-old man was a divorcee living with his 65-year-old mother and 16-year-old son in a flat on the 15th floor of Tin Hor House in Tin Ping Estate, am730 reported.

At 4 am, the man was alone in the apartment as his mother and son were away when a fire broke out followed by an explosion.

The man was injured and was seen climbing out a window. He climbed down to the 14th floor to ask for help and was rescued by a neighbor, who dragged him into the flat.

Firemen arrived and evacuated 700 residents. They put out the fire in 45 minutes.

The man suffered severe burns and was sent to the Prince of Wales Hospital where he was in a critical condition. Three men aged between 68 an 86 were also sent to hospital after inhaling smoke.

The man had attempted to commit suicide by cutting the gas line and starting a fire after taking zopiclone, news website HK01.com reported. Meanwhile, residents of Tin Hor House complained that the fire alarm malfunctioned, Oriental Daily reported.

A resident living on the 15th floor said he woke up due to the explosion and discovered heavy smoke in the corridor. He used a metal hand tool to break the glass on the fire alarm, but it did not activate.

The fire department said it will investigate the malfunction. The Samaritans run a 24-hour multilingual suicide prevention hotline +852 2896 0000 or emails can be sent to jo@samaritans.org.hk.