Firefighters battled one of Hong Kong's deadliest modern blazes for a second day Thursday, fighting to control the fire that blackened several high-rise towers and killed at least 65 people. Three men from a construction company were arrested, and rescues were continuing.

Thick smoke still poured out of the Wang Fuk Court complex in Tai Po district, a northern suburb near the border with the mainland, Thursday morning. The fire that started mid afternoon Wednesday had spread across seven of the complex's eight buildings, and four of the towers were under control by morning, the city's fire services said.

One firefighter was among the 65 people confirmed dead, officials said. At least 70 people were injured, many suffering from burn and inhalation injuries.

Three men, the directors and an engineering consultant of a construction company, were arrested on suspicion of manslaughter.

"We have reason to believe that those in charge of the construction company were grossly negligent,” said Eileen Chung, a senior superintendent of police.

Authorities suspected some materials on the exterior walls of the high-rise buildings did not meet fire resistance standards, allowing the unusually fast spread of the fire.

Police also said they found Styrofoam – which is highly flammable – attached to the windows on each floor near the elevator lobby of the one unaffected tower. It was believed to have been installed by the construction company but the purpose was not clear. Secretary for Security Chris Tang said they would investigate the materials further.

The fire started on the external scaffolding of a 32-story tower, then spread on the bamboo scaffolding and construction netting to the inside of the building and then to the other buildings, likely aided by windy conditions.

Firefighters aimed water at the intense flames from high on ladder trucks, but conditions for fighting the fire and rescuing people remained challenging.

“Debris and scaffolding of the affected buildings (is) falling down,” said Derek Armstrong Chan, deputy director of Fire Service operations. “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.”

The housing complex consisted of eight buildings with almost 2,000 apartments for about 4,800 residents, including many elderly people. It was built in the 1980s and had been undergoing a major renovation.

About 900 people were evacuated to temporary shelters overnight, and Hong Kong leader John Lee said 279 people were missing as of midnight. Rescues were continuing, but an updated figure wasn't available as of midmorning Thursday.

Lawrence Lee, a resident of the towers, was waiting for news about his wife, who was still trapped in their apartment.

“When the fire started, I told her on the phone to escape. But once she left the flat, the corridor and stairs were all filled with smoke and it was all dark, so she had no choice but to go back to the flat,” he said, as he waited in one of the shelters.

Lee, the Chief Executive, said the government will prioritize the disaster and halt promotion for the Dec. 7 elections for the Legislative Council, the city's legislature. He didn't say if the elections could be delayed but said decisions would come “a few days later”.

Chinese leader Xi Jinping expressed condolences to the firefighter who died and extended sympathies to the families of the victims, according to state broadcaster CCTV. He also urged efforts to minimize casualties and losses.

The fire was the deadliest in Hong Kong in decades. In November 1996, 41 people died in a commercial building in Kowloon in a fire that lasted for around 20 hours.