Errors in construction procedure were the main cause of the 13-story building toppling on Lianhua Road, Minhang District, Shanghai government officials said Friday at a press conference.

The toppled apartment building on Lianhua Road, Minhang District in Shanghai was seen in this picture taken on June 27, the day when the building collapsed.

Workers piled excavated earth up to 10 meters high on the north side of the building at Lotus Riverside complex while digging a 4.6-meter underground garage at the same time.

The pressure on both sides moved the foundations horizontally and they were unable to support the building, Huang Rong, director of the Shanghai Construction and Communication Commission, told a packed press conference.

The building toppled at about 6 am on June 27. One worker was killed.

There was no problem with the geological survey, design or construction materials, officials said.

After three days of emergency work, the garage has been filled with earth and the pile of earth outside is now only half a meter high.

The surrounding apartment houses have been declared structurally sound and safe.