A bridge over the Mississippi, linking Minneapolis and St Paul, collapsed on Wednesday night during evening rush-hour traffic, sending cars and trucks plunging into the river.
The entire span of the bridge, a major link between the two cities, fell apart in sections like an accordion, according to one witness.
The emergency services said that about 50 cars and trucks ended up in the river or on the ground below. People were seen floundering in the river, calling for help.
The mayor said at least nine people had died, and initial police reports said 37 had been injured. Police warned they expected the toll to rise.
Dr Joseph Clinton, who works at the Hennipin county hospital, said at least six who had been admitted were critical.
The United States Department of Homeland Security said the initial assessment was that there was no indication of terrorist involvement. Russ Knocke, a department spokesperson, said: ”At this time, there’s no indication of a nexus to terrorism.”
The bridge dropped about 18m.
Berndt Toivonen (51) of Minneapolis, told the Star Tribune he had been on his way home from a painting job when the bridge collapsed beneath his car. ”The bridge started to buckle,” Toivonen said. ”It went up and it came down. I thought I was going to die.”
He was uninjured, but he said people around him, some injured, were screaming in their cars as he went from vehicle to vehicle helping people out.
Joe Costello, a witness watching from a pedestrian bridge quarter of a mile away, said: ”I saw sand-coloured smoke 100ft [30m] up in the air and the bridge collapse, north to south, in sections. There was an eery silence at first. There was no reaction at first.”
The police said the cause of the collapse was unknown. But a witness told MSNBC television that he had heard a jackhammer being used on the roadway just before the collapse.
The steel and concrete bridge, built only in 1967, was 152m long and carried an average of 200 000 vehicles a day.
Senator Norm Coleman, who represents the state, said the bridge had been inspected in 2004 and been given a clean bill of health.
Hours after the collapse, smoke was still billowing from the wreckage and at least one truck was on fire. Dozens of cars lay scattered the length of the bridge, some piled one on top of another, some enmeshed in steel girders, others covered in rubble. About eight cars were partially submerged in the river.
Some survivors were left stranded on portions of the bridge. A school bus lay at an angle on a sloping slab of concrete, but the children appear to have escaped unhurt through the back door.
The rescue services were on the scene quickly and took the injured onto the riverbank. Divers were also quickly into the water to search for survivors.
There had been construction work on the bridge, which carries the 35W Interstate, through the summer but locals said it was not structural but confined mainly to resurfacing. – Guardian Unlimited Â