Miami bridge collapse: Four dead as new pedestrian crossing at Florida university crushes cars below

A newly constructed pedestrian bridge spanning several lanes of traffic collapsed at Florida International University on Thursday, killing four people.

Emergency personnel with sniffer dogs searched for signs of life amid the wreckage of concrete slabs and twisted metal after the bridge crushed vehicles on one of the busiest roads in South Florida.

"We have located up to four victims. Four deceased," Miami-Dade Fire Chief Dave Downey told a news conference.

Maurice Kemp, the area's deputy mayor, said the search for survivors had not yet been abandoned.

Built using "accelerated bridge construction" to avoid having to disrupt traffic, the bridge had been erected on Saturday in six hours.

At least eight vehicles were trapped in the wreckage of the 950-ton bridge and at least 10 people have been transported to hospitals, officials and doctors told news conferences.

"We're working our way into the pile trying to create holes that we can actually physically see," Miami-Dade Fire Department Division Chief Paul Estopian told reporters.

At one point, police requested television helicopters leave the area so rescuers could hear for any sounds of people crying for help from beneath the collapsed structure, CBS Miami television said.

Witnesses told local media the vehicles were stopped at a traffic light when the bridge collapsed on top of them at around 1.30 pm ET (17.30 GMT).

Witness Lynell Collins told CNN: "I was about to make a right turn, a few seconds before the bridge, and the whole thing came down.

"I was freaking out. I got out of my car, and me and some other people, we started trying to help but we couldn't really go under the rubble. Somebody we helped out said his family was still inside and he couldn't get them out. I saw two trucks completely crushed."

He said it was still a construction scene and nobody had been walking across the bridge

Isabella Carrasco and her boyfriend had driven under the bridge just before it collapsed.

She told CNN: "We heard a bang behind us. The cars were completely crushed under a lot of debris. I saw about five or six that were completely crushed but there could have been more I couldn't see.

"One woman was alive. The bridge hit the back of her car and she was able to get out. Another person was able to get out and they were performing CPR.

"There were a lot of students a lot of pedestrians. Thank God it's spring break so there was less traffic."

Tiona Page, a witness, said: she heard "terrifying" screams coming from the trapped cars.

She told ABC News: "As soon as I looked outside, I saw dust flying everywhere. I knew the bridge had collapsed."

Several people were seen being loaded onto ambulances.

The $14 million bridge, over a busy motorway, had only been erected on Saturday.

The main part of the 174-foot span was assembled by the side of the road while support towers were built at either end.

Miami-Dade Fire Rescue Department tweeted Thursday afternoon that "multiple patients" had been injured and officials were working to confirm how many. It also said it was securing the structure while searching for injured people.

Andy Herman, former president of the American Society of Engineers said it would be a "very delicate" operation to remove the bridge.

He said: "It's similar to earthquake damage. They have to make sure when they're lifting individual pieces they don't hurt anyone who is under there."

In a statement the university said: "We are shocked and saddened about the tragic events unfolding on campus. At this time we are still involved in rescue efforts and gathering information.

"We are working closely with authorities and first responders on the scene."