Firefighters rescue a 6-year-old girl from the rubble after four buildings collapsed in Wenzhou, Zhejiang province, on Monday. [Photo by YU GENLING/CHINA DAILY]

Seventeen people were declared dead after four residential buildings in Wenzhou, Zhejiang province, collapsed on Monday morning.

Nearly 800 rescuers are racing against the clock to search for missing people buried under debris, with the help of excavators, life-detection equipment and dogs.

The disaster happened around 4 am in Lucheng district. As of 8 pm, 23 people had been pulled from the rubble, but only six people, including a 6-year-old girl, survived.

Guo Lin was one of the first witnesses. He had been distributing leaflets and went to an internet bar to play online games overnight. About 3:40 am, he heard a loud sound and felt the room shake violently.

"My first thought was that it was an earthquake. So I stood up and tried to hide under the desk," Guo said. "Then I heard a woman crying loudly for help. I ran up to the third floor and opened the window. The street was full of dust and I couldn't see anything. So I dialed the emergency number 110."

There were three more people in the bar who tried to go out to check the situation. But the bar owner stopped them.

"He told us the street is full of rubble and we might be in danger if we went out. So we stayed in the house until the police came and knocked on our door," Guo said.

According to the neighbors, the four collapsed buildings were three to five stories tall and were built by local residents in the 1970s. This area was put on the demolition list two or three years ago, but work was somehow halted halfway. Most residents had already moved out, but some migrant workers were renting rooms at 200 yuan ($32) per month.

"They lost their lives to take advantage of cheap rent. It is horrible," Guo said.

Xu Shiyao stood anxiously outside the cordon. His 31-year-old younger brother was buried in the rubble and is still missing.

Xu and his brother, Huang Jianshuang, were from neighboring Yongjia county, about 30 km away. Huang worked for a local factory and lived in the collapsed building during the workweek.

"Usually my brother will come home on the weekend and go back to the factory on Monday morning, but last weekend he did not come back and he did not tell us the reason," Xu said.

"About 9 am I received a call from the factory and they told me he did not show up at work this morning. My whole family rushed here and we have waited here since 10 am. We don't have any trace of him."

According to the latest information on Lucheng district's micro blog page, in addition to the collapsed buildings five nearby dilapidated buildings were badly damaged.

Rescue teams were starting to pull down these buildings to avoid potential danger.