SEATTLE — Four people died and three were injured when a construction crane on the new Google Seattle campus collapsed Saturday, pinning six cars underneath.

One female and three males were dead by the time firefighters got to the scene, Fire Chief Harold Scoggins said. He said two of the dead were crane operators and the other two were people who had been in cars.

A 25-year-old mother and her 4-month-old daughter as well as a 28-year-old man were taken to Harborview Medical Center, according to Seattle Fire spokesman Lance Garland. A fourth person also was injured and treated at the scene.

Harborview spokeswoman Susan Gregg said Saturday evening that the mother and baby would be discharged, while the man injured was in satisfactory condition.

The King County Medical Examiner's Office said it would not release names of people who died until Monday.

"My thoughts and prayers are with those killed and injured," Seattle Mayor Jenny Durkan said on Twitter.

The crane collapsed near the intersection of Mercer Street and Fairview Avenue near Interstate 5 shortly before 3:30 p.m., Scoggins said.

With Amazon and other tech companies increasing their hiring in Seattle, the city has dozens of construction cranes building office towers and apartment buildings. As of January, there were about 60 construction cranes in Seattle, more than any other American city.

Scoggins said officials do not yet know the cause of the collapse.

Emergency crews work the scene of a construction crane collapse near the intersection of Mercer Street and Fairview Avenue near Interstate 5 in Seattle, on Saturday, April 27, 2019. (Joshua Bessex/The News Tribune via AP)AP

Daren Konopaski, the business manager for the International Union of Operating Engineers Local 302, which represents heavy-equipment operators, told The Seattle Times he understood the crane was being dismantled when heavy winds moved through the area.

"We don't know, but that's what seems to have happened here," he said. "We are in the process of trying to get information."

The National Weather Service in Seattle said a line of showers moved over Seattle just about the time the crane fell. An observation station on nearby Lake Union showed winds kicked up with gusts of up to 23 mph at 3:28 p.m., just about the time officials said the crane fell.

"It was terrifying," witness Esther Nelson, a biotech researcher who was working in a building nearby, told the newspaper.

"The wind was blowing really strong," she said, and added that the crane appeared to break in half. "Half of it was flying down sideways on the building," she said. "The other half fell down on the street, crossing both lanes of traffic."

The office building the crane fell from was badly damaged, with several of its windows smashed.

A crane collapsed in the Seattle suburb of Bellevue in 2006, damaging three neighboring buildings and killing a Microsoft attorney who was sitting in his living room. The state Department of Labor and Industries cited two companies for workplace-safety violations after an investigation that found a flawed design for the crane's base.

"Trudi and I join all Washingtonians in extending our deepest condolences to the family and friends of the four people who died in this afternoon's tragic accident," Washington state Gov. Jay Inslee said in a statement. Inslee also said he hoped for a speedy and full recovery for those injured, thanked first responders and urged people to stay clear of the accident scene.

Assistant Police Chief of Patrol Operations Eric Greening said all lanes may be closed until Sunday night.

-- By Lisa Baumann and Nicholas K. Geranios