By Dakin Andone and Steve Almasy, CNN

(CNN) -- At least four people died Thursday when a pedestrian bridge collapsed near Florida International University, Miami-Dade County Fire Chief Dave Downey said.

At least eight cars were crushed under the bridge and at least nine people were transported to hospitals for treatment, authorities said.

"The most important thing we can do right now is pray for the individuals who ended up in the hospital, for their full recovery, and pray for the family members who lost loved ones," Florida Gov. Rick Scott said Thursday night.

Scott said the state would do its best to determine if any wrongdoing led to the collapse and, if so, that people would be held accountable.

The bridge's span was just installed Saturday, an effort to boost safety on a busy street where an FIU student was fatally struck by a vehicle last year.

It is unclear why the bridge, which was still under construction, collapsed onto a busy state highway.

Latest developments

• Downey said the four deceased victims were located but have not been identified.

• Florida International University president Mark Rosenberg said the university followed all the processes required during the building of the bridge, and all contractors are certified by the state.

• Searchers are still looking for victims, although officials don't know if anyone is trapped alive in the rubble.

• Dr. Mark G. McKenney, trauma medical director at Kendall Regional Medical Center, said his staff received 10 patients, including two who are in critical condition. One patient with severe extremity injuries arrived in a coma, McKenney said.

Victims were trapped in cars beneath the rubble

"We heard a loud bang behind us ... and we looked back and the bridge had completely collapsed," said Isabella Carrasco, a student at the University of Miami, who had just passed underneath the bridge in a car. Doctors and medical students ran to the scene from a nearby building and started giving medical attention to victims, she said.

Florida Gov. Rick Scott was briefed on the incident by Perez, according to a schedule released by his office. He will be on the school's campus this evening to speak with local law enforcement and university officials, his office said.

Carrasco said she saw at least five or six cars completely crushed beneath the bridge.

"Someone on the side of the road had asked a police officer if she had heard any response from the people inside the car," Carrasco said, "and she shook her head and said no."

Ricardo Dejo, an FIU civil engineering student, told CNN he saw cars pinned beneath the bridge. "I can't describe it," Dejo said. "We were really excited about the bridge (before the crash). Everything looked fine. I went underneath it with my own car and it looked great."

Bridge was still under construction

In a statement, the university said it was "shocked and saddened about the tragic events unfolding at the FIU-Sweetwater pedestrian bridge."

"At this time we are still involved in rescue efforts and gathering information," the statement continued. "We are working closely with authorities and first responders on the scene."

According to a fact sheet about the bridge on FIU's website, it cost $14.2 million to build and was funded as part of a $19.4 million grant from the US Department of Transportation. It was designed to withstand the strength of a Category 5 hurricane, the fact sheet said, and was supposed to last for more than 100 years.

The bridge was supposed to open to foot traffic and cyclists in 2019.

"Our family's thoughts and prayers go out to everyone affected by this terrible tragedy," MCM, one of the companies that was contributing to the construction of the bridge, said in a statement. "The new University City Bridge, which was under construction, experienced a catastrophic collapse causing injuries and loss of life."

The statement added that MCM, which is based in Miami, would "conduct a full investigation to determine exactly what went wrong and will cooperate with investigators on scene in every way."

The company is also dealing with a lawsuit filed by a TSA employee, who claims a "makeshift" bridge for employees at an MCM construction area at Fort Lauderdale-Hollywood International Airport collapsed under his weight, severely injuring him.

Another company involved, FIGG Bridge Engineers, which designed the pedestrian bridge, said in a statement that it was "stunned" by the collapse.

"Our deepest sympathies are with all those affected by this accident," the FIGG statement said. "We will fully cooperate with every appropriate authority in reviewing what happened and why. In our 40-year history, nothing like this has ever happened before." FIGG is based in Tallahassee.

Bolton Perez and Associates, a third company involved in the construction of the bridge, is not commenting at this time.

BDI Engineering, a Colorado-based company, said it provided structural monitoring as the bridge span was put into place Saturday but added later that none of its personnel were at the scene on Thursday.

The company, which tweeted a video Saturday of the move and later took down the post, said it had "removed comments from our social media accounts out of respect for the individuals and families that have been affected by the collapse."

Its tweet on Saturday said that the firm was "thrilled to have performed structural monitoring during a spectacular bridge move."

Time-saving technology used to build the bridge

A statement from the university said that Accelerated Bridge Construction (ABC) technology was used in the construction of the pedestrian bridge.

ABC streamlines the building process so bridge construction projects can be completed quicker and be more cost-efficient. State Departments of Transportation use ABC technology to refurbish or construct bridges within 48 to 72 hours, according to the Federal Highway Administration (FHA).

By accelerating the time it takes to build the bridge, traffic delays and road closures can be reduced. It's also credited for safer work zones, less environmental impact, reduced weather-related delays and bridges that are more durable than those constructed using traditional methods, according to the FHA.

The 950-ton bridge was meant to connect the school's campus to the Sweetwater neighborhood, home to more than 4,000 FIU students, according to a press release on the school's website.

Jorge Munilla, president of MCM, told CNN affiliate WSVN on March 10 the bridge's construction was the realization of a dream. Munilla spoke as the bridge's span was installed over the street.

"Now that dream is becoming reality," he said. "The reality is, what makes this job so unique is that we built this bridge on the FIU campus over the last 6 to 7 months."

A National Transportation Safety Board team of 15 investigators is in Miami and will lead the federal inquiry.