One worker was killed and three others injured on Monday morning at a construction site in Shanghai after a 400-meter-high tower crane collapsed, local police announced.

At about 9 AM Monday in Pudong District, a worker was testing the huge tower crane by loosening the screws at the foot of the machine, triggering the collapse, said the police. A witness said the crane tumbled onto an unfinished building nearby and crushed the roof of the building before it hit the ground.

The worker who was testing the crane was crushed to death. Three other workers, who were buried in the building ruins, were hospitalized. One of the injured is in a critical condition, according to local hospital.

Investigations into the accident are underway.

(Xinhua News Agency June 6, 2005)