At least 44 people have been killed in a huge fire that has engulfed multiple high-rise buildings in Hong Kong’s Tai Po district.

There are reports that some residents were trapped in the building, and police say 279 people are still missing.

More than 760 firefighters were deployed to tackle the blaze on Wednesday afternoon, with pictures showing flames and thick clouds of grey smoke billowing from the towers, dominating the city’s skyline.

Three men have since been arrested on suspicion of manslaughter connected to the fire, according to local media reports, and an investigation has been launched.

The blaze broke out at the Wang Fuk Court housing complex at 14:51 local time (06:51 GMT) and was classified as a level five – the highest in severity – by the fire department at 18:22.

The cause is unknown, but the flames are believed to have spread quickly through the bamboo scaffolding that covered the outside of the buildings, which were undergoing renovations.

Among those hospitalised, 45 are in a serious condition. The injured were sent to hospitals in various districts.

Firefighter Ho Wai-ho, 37, was among those killed in the blaze. He was found collapsed at the scene about 30 minutes after contact with him was lost.

“I extend my deepest condolences to the deceased and my heartfelt sympathies to their families and the injured. We will provide all possible support,” he said.

The fierce heat of the blaze, as well as dangerous debris has hampered rescue efforts.

“The temperature inside the buildings concerned are very high, so it’s quite difficult for us to enter… and go upstairs to conduct firefighting and rescue operation,” said Derek Armstrong Chan, the deputy director of fire services.

The fire has yet to be extinguished and officials have said they were unsure when it would be.

Wang Fuk Court was built in 1983 and is made up of eight tower blocks that provide 1,984 apartments for some 4,600 residents, according to a 2021 government census. Seven of the towers have been affected by the fire.

Some residents have told local media that the fire alarms did not sound, and when the elevators stopped working, they struggled to get out. A local councillor said many of the people who lived at Wang Fuk Court are elderly.

There were also reports on Wednesday night of blasts being heard from inside the buildings, and fire hoses were struggling to reach the upper levels of the 31-storey towers.

Preliminary investigations found that the rapid spread of the fire was suspicious, Hong Kong’s security secretary, Chris Tang, was quoted to have said in local media. This included the use of polystyrene to seal windows.

Police have also evacuated nearby buildings, and several temporary shelters have been opened. One of the shelters, located over the road from the housing complex, was deemed unsafe as the fire continued to rage, and evacuees were directed to another further away.

An officer at a temporary shelter told the AFP news agency it was unclear how many people were unaccounted for because residents were still trickling in late into the night to report missing family members.

There is a large evacuation zone around the fire, roads are closed and more than 30 bus routes have been diverted, Hong Kong’s Transport Department says.

China’s President Xi Jinping has expressed sympathy for the victims and urged that every effort be made to put out the fire and minimise the losses, state media reported.

The use of bamboo scaffolding is common in Hong Kong and it is one of the last cities in the world to still use it in modern construction.

According to local media reports in March, the government’s development bureau has been trying to phase it out, in favour of metal scaffolding, due to safety concerns.

It has been 17 years since Hong Kong faced a level five fire, when a building constructed in 1962, Cornwall Court, burnt down. Four people were killed in that fire.

Additional reporting by Tiffany Wertheimer.