Three people, including one who sustained burn injuries, were assessed for smoke inhalation and taken to the hospital after a fire broke out early Thursday morning in a residential building in eastern Singapore, the Singapore Civil Defense Force (SCDF) said.

A total of six people were rescued. The remaining three did not require ambulance assistance.

About 100 people had evacuated on their own before SCDF crews arrived. The fire broke out in a two-story unit on the 14th floor, where crews heard calls for help. Four of the six residents were rescued from the first level and two from the second.

The fire, which involved the kitchen and living room on the first level, was extinguished with one water jet. The rest of the unit suffered varying degrees of heat and smoke damage.

The SCDF said the cause of the fire is under investigation.