A unit in Neptune Court condominium near East Coast Park was seen ablazed about an hour ago.
The unit is believed to be either on the 15th or 16th floor.
Mr Salil Khot, who stays opposite the block, called the MediaCorp news hotline and gave more details.
"The fire was really huge, and then it spread from the hall to the bedroom. The fire was contained in the hall but it still exist in the bedroom. And the firemen are still trying to contain that. But they're still trying."
At around 6pm, Mr Khot said the firemen were seen trying to access the flat.
"The glass breaking down, or being broken by the firemen. And the glass pieces are falling down."
Another caller to the hotline, who only gave his name as Roy, said that he could hear people screaming and dogs barking.
SCDF has confirmed the fire, but was unable to provide more details.
Stay tuned as we bring your more information.