The fire that partly destroyed one of the main attractions of the planned Ninth China (Beijing) International Garden Expo might have been caused by illegal hot work, authorities said.

The Beijing Municipal Commission of Housing and Urban-Rural Development said the investigation points to hot work as the cause of the blaze on Monday that destroyed part of the Yongding tower in Beijing's Fengtai district.

Investigators are appraising losses from the fire and drawing up a repair plan, said Gu Xiaoyuan, a publicity officer for the expo.