Multiple cars and people were trapped under a newly constructed bridge at Miami's Florida International University after it collapsed Thursday.
Fire officials said there are at least four fatalities. At least nine victims have been taken to Kendall Regional Medical Center.
The Miami-Dade homicide bureau is leading an investigation into the collapse.
A newly erected pedestrian bridge collapsed across a multi-lane road in Miami on Thursday afternoon, trapping cars underneath and killing at least four people.
The 950-ton bridge, built to provide a safer crossing for students at Florida International University, collapsed about 1:30 p.m. Fire Chief Dave Downey of Miami-Dade Fire Rescue confirmed at a news conference Thursday night that there were at least four fatalities. At least nine people were hospitalized, he added.
Earlier Thursday, the city's Kendall Regional Medical Center said that it had received 10 patients and that two were in critical condition. The patients were 20 to 50 years old.
Miami-Dade Fire Rescue said that eight vehicles were trapped under the collapsed bridge.
First responders are continuing to search for more victims. Officials said the bridge has to be removed piece by piece because of its instability.
"The next few hours are going to be a rescue mission," Miami-Dade Police Chief Juan Perez said at the first press conference, noting that his department's homicide bureau would take the lead on the investigation and that the state attorney was "on standby."
The bridge stretched along FIU's campus, across Southwest Eighth Street, and had not yet opened to pedestrians. It was only lifted into place on Saturday and was still under construction with completion expected by early 2019, according to the school.
An emotionally distressed Mario Valdez was interviewed by WSVN at the scene and said that he'd heard his friend was walking beneath the bridge when it abruptly collapsed on him.
"He was crossing the street at the moment that the bridge was coming down," Valdez told the local station. "He was rushed to the hospital. I don't know. I'm just so worried."
Valdez declined to identify his friend, as the friend's mother is out of town.
Twitter user Damani Reed, who told HuffPost that he heard the bridge collapse from a nearby apartment building, snapped a photo that showed the destruction spread across the multiple-lane road.
"It wasn't too loud it sounded like two metal walls fell over," Reed wrote HuffPost.
FIU released a statement saying that it was "shocked and saddened about the tragic events unfolding" and that it would share updates "as we have them."
The university had previously boasted that the bridge was designed to withstand a Category 5 hurricane and last for at least 100 years. It was built using a method known as accelerated bridge construction, in which most of the bridge was built off-site, away from where it would ultimately be installed. The university called it "the largest pedestrian bridge move in U.S. history."
Barnhart Crane and Rigging, the company contracted to move the bridge into place last weekend, told HuffPost that it was not involved with the structure's design or construction.
"Our scope of work was completed without incident and according to all technical requirements," the company's statement read. "Barnhart crews and equipment were not on site at the time of the incident. We will fully cooperate with authorities as they investigate the cause of the collapse."
Munilla Construction Management, which built the bridge, also released a statement on Facebook that described its staff as "devastated" by the catastrophe. The Miami company vowed a full investigation.
"Our family's thoughts and prayers go out to everyone affected by this terrible tragedy. The new UniversityCity Bridge, which was under construction, experienced a catastrophic collapse causing injuries and loss of life," the statement read.
Munilla Construction was awarded the $9.3 million bridge project in partnership with FIGG Bridge Group. It was designed to connect the university's Modesto A. Maidique Campus with the city of Sweetwater, according to the school's website.
The construction company has been cited in the past for unsafe practices that led to employee injuries, the Miami New Times reported. It is currently facing a lawsuit from a Transportation Security Administration employee who says a temporary walkway that the company built at Fort Lauderdale-Hollywood International Airport in 2016 collapsed underneath him, sending him crashing to the ground and causing him multiple injuries.
FIGG Bridge Group, the designer behind the FIU span, was fined $28,000 after another bridge in Virginia collapsed mid-construction and left four workers with minor injuries, the Miami New Times also reported. The company had violated several safety rules, the state found, and was lucky that no one died in the accident.
Florida Gov. Rick Scott (R) said on Twitter midday that he had been in contact with Chief Perez about the collapse and was heading to the university. The National Transportation Safety Board announced that it was sending investigators to the scene.
President Donald Trump has been briefed about the situation, White House press secretary Sarah Huckabee Sanders told reporters.
This article has been updated with information from Miami-Dade Fire Rescue on Thursday night.