A newly installed pedestrian bridge spanning several lanes of traffic collapsed in Miami on Thursday, killing four people and trapping multiple cars below. Emergency personnel with sniffer dogs searched for signs of life amid the wreckage of concrete slabs and twisted metal after the 950-ton bridge crushed vehicles on one of the busiest roads in South Florida. The walkway, which connected Florida International University to a student housing area, went up less than a week ago. "We have located up to four victims. Four deceased," Miami-Dade Fire Chief Dave Downey told a news conference. Maurice Kemp, the areas deputy mayor, said the search for survivors had not yet been abandoned. "Miami-Dade county and our partner agencies... have been working feverishly in the search and rescue mode to ascertain how many victims there are and rescue as many as we can," Kemp told journalists. Miami-Dade Fire Rescue Division Chief Paul Estopinan said at least eight cars were trapped when the bridge suddenly gave way. “Continuing to monitor the heartbreaking bridge collapse at FIU - so tragic. Many brave First Responders rushed in to save lives. Thank you for your courage,” US President Donald Trump tweeted. “Praying this evening for all who are affected,” he said. Bridge collapses in the United States are infrequent despite rising risks associated with aging infrastructure. The deadliest this century was the 2007 collapse of an eight-lane bridge in Minneapolis, Minnesota, which killed 13 people.