Four people have been killed after a newly installed pedestrian bridge spanning several lanes of traffic collapsed at Florida International University, officials have said.
Emergency personnel searched for signs of life amid the wreckage of concrete, twisted metal and crushed vehicles on one of the busiest roads in South Florida.
At least ten injured people were taken away from the scene and eight vehicles were trapped in the bridge wreckage, Miami-Dade County Mayor Carlos Gimenez said.
There were at least five to six vehicles crushed underneath the pedestrian crosswalk, he added.
Police had requested television helicopters to leave the area so rescuers could hear for any sounds of people crying for help from beneath the collapsed structure.
Munilla Construction Management, which installed the bridge, in a statement on Twitter, said the bridge suffered a "catastrophic collapse causing injuries and loss of life."
Complicating the rescue effort was the uncertainty about the integrity of the bridge, parts of which remained off the ground, much of it inclined, local media reported.
Miami police warned people to avoid the area.
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 53m long and weighed 950 tons.
The $14.2 million bridge was designed to withstand a Category 5 hurricane, the most dangerous measure by the National Hurricane Centre, and built to last 100 years, the university said.
#MDFRUpdate: There are multiple patients injured. We’re working on confirming numbers. Please continue to follow us on Twitter for updates. https://t.co/FVjUJndqYH
— MDFR (@MiamiDadeFire) March 15, 2018
The bridge was intended to provide a walkway over southwest Eighth Street, one of the busiest roads in South Florida.
Television footage showed firefighters were walking across the flattened wreckage and medics treating injured people.
Emergency personnel appeared to be trying to work their way through a hole in the top of the bridge.
White House spokeswoman Sarah Sanders said President Donald Trump is aware of the collapse.
"Our brave first responders are working feverishly to save lives," she said at a news briefing.
Florida Governor Rick Scott will head to the scene later in the day, his office said.
The National Transportation Safety Board said on Twitter that it was sending a team to investigate the bridge collapse.
Munilla Construction Management was founded in 1983 and owned by five brothers, according to its website.
In addition to its Florida operations, the company also has divisions in Texas and Panama and employs 500 people.
