Police in Kenya’s capital said Thursday that nine people are dead after a crane collapsed at a high-rise construction site in Nairobi.

The crane tower was left standing alone after the jib crashed to the ground.

Officer Muturi Mbogo said the crane collapsed midday Thursday while it was being dismantled by workers. He said another worker was seriously injured. He said the collapse is under investigation.

A worker at the site, Michael Odhiambo, said the crane fell after its work was completed on the 14th floor.

“It seems they did not realize the nuts tying it was loose,” he said of fellow workers. “We heard a loud bang, only to realize the crane was down.”

Two Chinese engineers were among the victims, Odhiambo said. The project to build a 14-story student hostel is being supervised by a Chinese construction firm.

Plumber Dominic Morara told the AP that he saw workers fall from the crane and that those on the ground fled the area.