At least 36 people were killed and 279 were unaccounted for in Hong Kong after a massive fire tore through a complex of residential high-rise buildings, city leader John Lee said on Thursday.

Lee said at a press briefing that 29 people were still hospitalised, with seven of them in critical condition.

Since Wednesday afternoon, teams of firefighters have been attempting to douse the flames at Wang Fuk Court, a housing complex made up of eight blocks in the city's Tai Po district in the north east. The fire was still burning in the early hours of Thursday.

What we know about the fire

The fire department said it received reports on Wednesday at 2:51 p.m. (0651 GMT) of a fire in the residential complex. It was upgraded to a Number 4 alarm at 3:34 p.m. and as night fell it was declared a five-alarm fire, the highest level.

Firefighters deployed 128 fire trucks and 57 ambulances to the scene.

"Debris and scaffolding of the affected buildings are falling down," said deputy director of Fire Services Derek Armstrong Chan.

"The temperature inside the buildings concerned (is) very high. It's difficult for us to enter the building and go upstairs to conduct firefighting and rescue operations."

Reports some residents trapped

Earlier, local media had reported that an unknown number of people were trapped in the 31-storey towers — housing around 2,000 residential apartments.

Taipo District Council member, Lo Hiu-fung, told local broadcaster TVB that most of the residents trapped in the fire were believed to be elderly people.

A number of towers currently burning have bamboo scaffolding and construction netting fitted to their exterior.

TVB reported that the complex was undergoing major renovations.

Smoke and flames still billowing from building complex

Live footage from the Reuters news agency showed large columns of smoke billowing from several buildings and as darkness fell, fires could be seen burning on multiple floors and apartments of the complex. 

"Residents nearby are advised to stay indoors, close their doors and windows, and stay calm,"  the Fire Services Department said.

Parts of a nearby highway have been closed by the ongoing firefighting operation.

Tai Po is a suburban area situated in the northern part of Hong Kong, near the border with the mainland Chinese city of Shenzhen.

Edited by Sean Sinico