Experts in construction, geology and hydrology said neither the 10 buildings being built near the collapsed block, nor other houses nearby had shown signs of slanting, moving or sinking after the accident, which they attributed to the movement of a large amount of dirt around the estate, China News Service reported yesterday.

However, two independent construction professionals who inspected all the buildings found at least three others under construction in the Lotus Riverside estate were leaning and could fall suddenly, the Hong Kong-based Information Centre for Human Rights and Democracy said in a press release yesterday.

A nearly completed 13-storey building collapsed on Saturday, killing one person. Nearby residents were evacuated and given hotel rooms on Saturday night.

A construction team worked at the site through Saturday night to prevent disasters that could be caused by the accident, an official told the Xinmin Evening News. The government said it had also launched safety checks on all construction projects in the city.

About 400 of the 489 homebuyers in the estate have filed requests to cancel their purchases and get their money back. Dozens of them went to Shanghai's petition office yesterday, calling for the government's help.

"Our flats are in the same area as the collapsed building. There is no way our flats are not affected," one owner told Hong Kong's Cable TV. "It is possible that the base of our building is not stable. We are worried."

About 200 homebuyers have drafted a letter to Shanghai Communist Party chief Yu Zhengsheng and Mayor Han Zheng to list their demands. They want their money back and additional compensation within a month and asked the government to announce the causes and list the people responsible for the accident within one week.

The estate's developer, Shanghai Meidu Property Development, has not commented since the accident.

Besides Lotus Riverside, the developer has two other estates in Shanghai, and has sold 243 of 325 flats in them. The human rights information centre said many homebuyers in those estates were also worried about the quality of their flats, and demanded that the government announce the cause of the accident.