Hong Kong’s worst fire disaster in seven decades continued to unfold on Thursday as firefighters struggled to put out a massive blaze that engulfed seven residential towers in Tai Po, pushing the death toll to 83 and leaving more than 280 people unaccounted for.

Rescuers holding flashlights were going from apartment to apartment at the charred towers as thick smoke continued to pour out from some windows at the Wang Fuk Court complex, a dense cluster of buildings housing thousands of people in Tai Po district, a northern suburb near Hong Kong’s border with the mainland.

It was unclear how many people were missing or trapped. Hong Kong leader John Lee said contact had been lost with 279 people early Thursday.

Authorities did not provide updates on the missing people or how many were still inside the ravaged buildings on Thursday during a press conference.

The latest video showed rescuers searching in some apartments in the dark. Orange flames were still seen from inside several windows, though the whole complex was now largely a blackened ruin.

Firefighters have been trying to control the flames since midafternoon Wednesday, when the fire was believed to have started in bamboo scaffolding and construction netting and then spread across seven of the complex’s eight buildings. Fires in four buildings had been effectively put out, with the remaining three towers under control, authorities said Thursday afternoon.

Rescuers are “battling high temperatures and carefully going up floor by floor, thoroughly searching and aiming to rescue people as quickly as possible,” said Wong Ka-wing, deputy director of the fire services. “(We) don’t rule out rescuing more injured people.”

More than 70 people were injured, including 11 firefighters, the Fire Services Department said.

About 900 people were evacuated to temporary shelters overnight.