The Ninth China (Beijing) International Garden Expo might be delayed after a fire on Monday partly destroyed one of the event's main attractions, authorities said.

The blaze destroyed part of the Yongding Tower in Beijing's Fengtai district, where the event will be held, said Yang Guang, a spokeswoman for the district.

Firefighters battle a fire on Yongding Tower, one of the major buildings of the Ninth China (Beijing) International Garden Expo, on Monday. Wang Jing / China Daily

"So far, it's hard to tell whether the damage caused by fire will delay the expo, and the cause of the fire is still under investigation," said Yang. "But we'll further look into it and make sure the expo is held in time."

Yang said that damage to the tower is likely limited.

The expo, jointly organized by the Ministry of Housing and Urban-Rural Development and Beijing municipal government, was initially expected to welcome its first visitors on May 18.

The event, which was designed to contribute to the improvement of the city's scenery, was expected to run from May to November with 46 exhibitions from 60 cities.

Infrastructure projects such as subway stations and roads are being built in the area.

The fire, which hit the Yongding Tower at about 3 pm, was made worse by the strong winds felt in the capital on Monday, according to the expo's organizing committee.

Firefighters rushed to the site immediately after the disaster, but the fire gradually increased with the aid of the strong winds, according to a construction worker named Liu, who witnessed the blaze.

The fire was put out at around 7:15 pm, authority said.

Construction workers living in tents near the site were evacuated.

No official explanation was given for the fire, but some local workers said that exhaustion due to overtime work might be one of the reasons.

"We've been working overtime for a long time, with many consecutive days working late into the night, until around 2 am," said a construction worker at the site.

Workers were making an effort to make sure that the expo will open on the expected date, he said.

Construction work will be suspended on Tuesday, and it's unknown when it will resume, Yang said.