At least 36 people have died in a major fire in several residential blocks in Hong Kong, with a further 279 people still missing, Hong Kong Chief Executive John Lee said in the early hours of Thursday morning.

This significantly increases the number of victims following the devastating fire at the Wang Fuk Court residential complex in the Tai Po district of the city, which is a special administrative region of China.

The authorities had already classified the fire as a level 5 emergency, the highest level, in the afternoon.

At least 29 injured people were treated in hospital. The cause of the fire remains unclear. The authorities have launched an investigation and intend to scrutinize the safety standards of the bamboo scaffolding and the green nets attached to the complex.

According to a report in Hong Kong's South China Morning Post, three men have been arrested on suspicion of manslaughter in connection with the fire.

The police said they will hold a press conference early Thursday to provide further details.

Lee: Fire slowly being brought under control

Among the dead was a firefighter, according to reports. As confirmed by the government of the Chinese special administrative region, the 37-year-old was found unconscious at the scene and was initially taken to hospital, where he later died from his injuries.

According to Lee, the emergency services gradually brought the flames under control, the Hong Kong-based South China Morning Post reported.

All available emergency services were to be mobilized to fight the flames, he added.

From Beijing, Chinese President Xi Jinping sent condolences, Chinese state television reported. He assured the special administrative region of support.

Fire engulfs several residential buildings

The flames had engulfed seven residential blocks of the complex, reports cited the fire brigade as saying.

Several calls were received from people trapped in their flats on Wednesday afternoon. The area comprises eight residential buildings, each with 32 storeys and a total of nearly 2,000 flats. The buildings were all surrounded by scaffolding for renovation work.

Photos and videos from the scene showed large plumes of smoke rising from the scaffolded high-rise residential buildings. It was also visible how the facade scaffolding was ablaze over several storeys, with burning debris falling to the ground. Additionally, fires could be seen inside individual flats.

Hundreds of emergency personnel on site

Residents near the scene were advised to keep windows and doors closed and to avoid the area around the burning buildings.

The Hong Kong police set up a telephone service for the public to obtain information about the victims.

The South China Morning Post reported that more than 800 firefighters and paramedics with over 140 vehicles were deployed.

Around 900 people sought shelter until late evening in the accommodation set up by the city.