This article is more than 2 years old

This article is more than 2 years old

Four people have been killed after a newly installed pedestrian bridge collapsed on Thursday at Florida International University in the Miami area, crushing at least five vehicles.

The 950-ton span fell directly on to a busy roadway at the university’s main Miami-area campus. Video shows vehicles underneath the bridge were hit.

At a news briefing Thursday evening, the Miami-Dade County fire chief said four had been found deceased at the scene by first responders. Nine victims were removed “early on” and taken to hospitals, Dave Downey added, but did not elaborate on their conditions.

Florida’s governor, Rick Scott, also spoke to reporters, saying: “Everybody is working hard to make sure we rescue anyone who can be rescued.” The governor added that an investigation would get to the bottom of “why this happened and what happened” and that anyone found responsible would be held accountable.

Dr Mark McKenney, the chief surgeon at Kendall regional medical centre’s trauma unit, said his hospital received 10 patients, two of whom he said remained in “an extremely critical condition” on Thursday evening, one with significant head and chest injuries and one in a coma.

Munilla Construction Management, which installed the bridge, said in a statement that the bridge suffered a “catastrophic collapse, causing injuries and loss of life”.

There were unconfirmed reports that workers were conducting a stress test on the bridge when it collapsed, and the Miami-Dade police chief, Juan Perez, said construction workers were believed to have been on top of the structure at the time.

The bridge connects the university with the city of Sweetwater and was installed on Saturday in six hours over the eight-lane highway, according to a story that was posted on the university’s website. It was 174ft (53 meters) long and weighed 950 tons.

Facebook Twitter Pinterest Vehicles are seen trapped under the collapsed pedestrian bridge. Photograph: Joe Raedle/Getty Images

The bridge was intended to provide a walkway over Southwest Eighth Street, one of the busiest roads in south Florida. An 18-year-old FIU student from San Diego was killed while trying to cross the street near campus last August, according to local media reports.

The White House press secretary, Sarah Sanders, said Donald Trump was aware of the collapse. “Our brave first responders are working feverishly to save lives,” she said at a news briefing.

The National Transportation Safety Board said on Twitter that it was sending a team to investigate the bridge collapse.

One witness on Thursday, speaking on CNN, said she heard “a loud bang” behind her just after she and her boyfriend had driven under the bridge and made a right turn into the FIU campus.

“We thought maybe someone had hit us. We looked back and the bridge had completely collapsed,” Isabella Carrasco said.

“We got out of the car. We saw police helping people, there was a construction worker injured at the side of the road. The cars were completely crushed, a lot of debris everywhere. One woman luckily made it out alive – it crushed the back of her car. She rolled forward and was able to get out.”

A statement from FIU addressed to “members of the university community”, while the rescue operation was still under way, said: “We are shocked and saddened about the tragic events unfolding at the FIU-Sweetwater pedestrian bridge.”

Facebook Twitter Pinterest View of the main span of the FIU-Sweetwater University City Bridge which collapsed five days after been installed. Photograph: Miami Herald/TNS/Sipa USA/Rex/Shutterstock

Another witness, Jonathan Munoz, a student, said he and a professor ran over after the collapse and saw “a scene of chaos”.

“I heard people were screaming. I thought it was a car accident,” Munoz told CNN. “This intersection is very busy. There have been fatalities from students being struck; that’s why they built the bridge.

“There were doctors from the medical school on campus who came over in their white coats, figuring out who they could immediately get to. There were police and construction workers. It was a chaotic scene. No one knew exactly what to do.”

According to the Miami Herald, construction crews had spent several months erecting support towers on either side of the roadway, and cranes lifted the walkway into place on Saturday morning.

The $14.2m project was funded by the US Department of Transportation.