Image copyright Reuters Image caption A section of the crane plunged into Mercer Street, Seattle

Four people were killed and three others injured when a construction crane collapsed in the US city of Seattle.

Cars were crushed when the crane fell from a building site and into a road in the South Lake Union district, the Seattle Fire Department said.

Two were killed working in the crane and two were killed in their cars.

A woman and her baby, and a man in his 20s, were injured and taken to hospital, officials said.

The incident happened at about 15:30 local time (22:30 GMT) on Saturday.

Witness Esther Nelson told the Seattle Times that the crane appeared to break in half during strong winds.

"Half of it was flying down sideways on the building, the other half fell down on the street, crossing both lanes of traffic," she said.

The building under construction was badly damaged. The development is to house a new Google Seattle campus and about 150 new flats, the Seattle Times reported.