Police in Hong Kong arrested three men on suspicion of manslaughter, several local news media reported, in connection with a blaze that has killed at least 36 people and left another 279 missing in the city’s deadliest fire in years.

Hundreds of residents were evacuated as the fire which started on Wednesday afternoon, spread across seven of the eight high-rise apartment buildings in a housing complex in Tai Po district, a suburb in the New Territories. At least 29 others remained hospitalized. Bright flames and smoke shot out of windows as night fell.

Authorities said earlier that investigators would be looking into factors including whether material on the exterior walls of high-rise buildings met fire resistance standards, as the rapid spread of the fire was unusual.

Officials said the fire started on the external scaffolding of one of the buildings, a 32-storey tower, and later spread to inside the building and then to nearby buildings, likely aided by windy conditions.