Rescuers search for survivors at a collapsed house in Beijing, capital of China, May 5, 2012. Four were killed and six others injured on Saturday, following the collapse of an illegal two-storey prefabricated house in Beijing's Chaoyang District. (Xinhua/Li Wen)

A two-story makeshift house, being built illegally, collapsed Saturday afternoon in Beijing, leaving four dead and six others injured, authorities said.

The injured have been rushed to hospital after the accident happened at about 1:40 p.m. at the Xizhihe village of Shibalidian Township in Chaoyang district, according to a spokesman with the Beijing municipal government.

By midnight Saturday, rescuers had finished searching work and no more casualties were found.

Police said the house under construction was unauthorized, and the cause of the accident is under investigation.