At least 55 people were killed after a massive fire tore through a high-rise housing complex in Hong Kong, authorities said Thursday, the city’s deadliest blaze in decades.

Hong Kong police said on Thursday the death toll in a fire that ripped through residential blocks in the city had risen to 40, with 45 people still in a critical condition.

Several people remain trapped inside the burning towers, public broadcaster RTHK reported, citing police.