[WATCH] At least 29 dead in fitness centre fire in South Korea

At least 29 killed and at least another 26 injured in a fire at a fitness centre in South Korea on Thursday.

The fire broke out around 4:00pm local time, and quickly engulfed the entire eight-storey building, leaving many trapped inside, in the southern city of Jecheon.

The fire is believed to have started in a parking lot on the first floor, and has since been mostly put out.

Many victims were trapped in a sauna on the second floor. Officials have said the death toll could rise as firefighters continue their search.

"The fire produced so much toxic smoke so quickly, leaving many people unable to evacuate," a spokesman at the National Fire Agency said.

Television footage showed the building consumed by flames and issuing dark plumes of smoke, as several people stood waiting to be rescued from an outdoor terrace.

Some 20 people were rescued from the rooftop after taking refuge from the fire. Several of the survivors were taken hospital to be treated for smoke inhalation, officials said.

As many as 60 firefighters attended the scene on Thursday in the city.

The building houses a fitness centre, restaurants and a public sauna.

Organizers for the Pyeongchang Winter Olympics said the Olympic torch relay had been scheduled to pass through Jecheon on Friday, but the route has been revised because of the tragedy.