HONG KONG, Dec 1 (Reuters): Hong Kong authorities said on Monday they had arrested 13 people for suspected manslaughter in a probe into the city's deadliest fire in decades, pointing to substandard renovation materials for fuelling a blaze that has claimed at least 151 lives.

Police continued to sweep the seven burnt-out towers engulfed in Wednesday's disaster at the Wang Fuk Court estate, finding bodies of residents in stairwells and on rooftops, trapped as they tried to flee the flames.

More than 40 people are still missing.

"Some of the bodies have turned into ash, therefore we might not be able to locate all missing individuals," police official Tsang Shuk-yin told reporters, choking up with emotion.

Tests on several samples of a green mesh that was wrapped around bamboo scaffolding on the buildings at the time of the blaze did not match fire retardant standards, officials overseeing the investigations told a news conference.

Contractors working on the renovations used these substandard materials in hard-to-reach areas, effectively hiding them from inspectors, said Chief Secretary Eric Chan.

Foam insulation used by contractors also fanned the flames and fire alarms at the complex were not working properly, officials have said.

Thousands have turned out to pay tribute to the victims, who include at least nine domestic helpers from Indonesia and one from the Philippines, with lines of mourners stretching more than a kilometre (a half-mile) along a canal next to the estate.

Vigils are also due to take place this week in Tokyo, London and Taipei, authorities said.
Amid pockets of public anger over missed fire risk warnings, Beijing has warned it would crack down on any "anti-China" protests.

At least one person involved in a petition calling for an independent probe and a review of construction oversight among other demands was detained for around two days, sources familiar with the matter said.

Police have declined to comment on the case.

Hong Kong Security Chief Chris Tang also declined to comment on specific operations at a press conference on Monday.

"I’ve noticed that some people with malicious intent, aiming to harm Hong Kong and national security, have taken advantage of this painful moment for society," he said.

"Therefore, we must take appropriate action, including enforcement measures."

Photo from Reuters