Chinese state media say unlicensed welders accidentally started a fire that killed 53 people in a high-rise apartment building in Shanghai.
Officials reported Tuesday that eight people have been detained in connection with the tragedy.
Witnesses say the fire spread from a scaffold on the outside of the 28-story building and quickly spread to engulf the entire apartment block, which was being renovated.
Many residents used the scaffolding to escape from the spectacular blaze, which began Monday afternoon and left more than 70 people hospitalized. Shanghai officials said more than 100 fire engines were dispatched to extinguish the fire.
Public Security Minister Meng Jianzhu, who was sent to Shanghai to oversee rescue efforts, said earlier that anyone found responsible for the fire will be punished.
China has been plagued by unsafe building work. The problem comes to light especially during earthquakes, fires and floods.
Some information for this report was provided by AP and AFP