SINGAPORE, June 19 (Xinhua) -- A fire broke out in a residential block in southern Singapore on Thursday night, sending four people to the hospital, according to the Singapore Civil Defence Force (SCDF).

Among them, two residents were assessed for smoke inhalation, while two firefighters suffered from heat exhaustion, the SCDF said on social media.

Firefighters found a bedroom in a 23rd-floor unit on fire. They entered the smoke-filled unit and extinguished the fire using two water jets.

Around 100 people were evacuated from the affected block. The cause of the fire is currently under investigation. ■