A devastating fire has ripped through several high-rise tower blocks in Hong Kong, killing at least 44 people, making it the deadliest in more than 60 years. More than 270 have been reported missing and thousands of residents are in evacuation shelters.

Pictures show several buildings ablaze, and thick smoke billowing into the air, dominating the Chinese territory's skyline.

As night fell, the fire was still burning hours after it was first reported, with more than 760 firefighters deployed to the scene.

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.

Chinese President Xi Jinping has expressed condolences to victims, including a 'firefighter who died in the line of duty', state media report.

What caused the blaze is still unclear, but here is what we do know, so far.

Where and when did the fire start?

The blaze broke out at Wang Fuk Court, a large housing complex in Hong Kong's Tai Po district, at 14:51 local time on Wednesday (06:51 GMT).

Wang Fuk Court consists of eight tower blocks, each 31 storeys high. Seven have been affected by the fire, Tai Po district councillor Mui Siu-fung told BBC Chinese.

Built in 1983, the tower blocks were undergoing renovations, and the outside of the buildings was covered in bamboo scaffolding and construction netting. Footage shows the fire spreading quickly through the bamboo.

A preliminary investigation found that the rapid spread of the fire was unusual, Hong Kong's security secretary said early on Thursday morning. One of the factors in this was said to be the use of polystyrene - which can be highly flammable - around windows.

How serious is the fire?

The Hong Kong fire department has classified the blaze as a level five alarm - the highest in severity.

Local media reported that explosions could be heard inside the building and fire hoses could not easily reach the higher levels.

What do we know about the victims?

The death toll rose significantly early on Thursday morning, from 13 to 36 people.

Among the dead is firefighter Ho Wai-ho, 37, who was with the service for nine years. He was found collapsed after rescuing others.

Emergency hotline and shelters set up

Several emergency shelters have been set up to accommodate evacuated residents, but some facilities were reported full. An emergency monitoring and support centre is in operation.

What do we know about the arrests?

Police arrested three men in connection to the blaze, including two construction firm directors. Authorities noted that safety failures contributed to the fire spread.

Hong Kong and bamboo scaffolding

The tower blocks at Wang Fuk Court are covered in bamboo scaffolding for renovations. Bamboo is an iconic yet controversial material due to fire safety concerns.