A bridge spanning the Mississippi River in the Midwestern city of Minneapolis collapsed Wednesday, during the evening rush hour, dumping scores of vehicles into the river. At least four people died and local hospitals have treated dozens of people for injuries. VOA's Greg Flakus has more on the story from Houston.

Officials say the Interstate 35 West bridge was crowded with about 50 vehicles when it collapsed. Part of the structure fell 18 meters into the river. Other sections fell back onto the river bank. Buses, trucks and automobiles crashed on top of one another, as they slid down the broken sections of the bridge. Some people who were able to get out of their vehicles managed to get off the damaged structure and to safety on the river bank. One man who escaped from his truck and got off the bridge spoke to the local Star Tribune newspaper by telephone.

"I fell probably 30 or 40 feet and landed on the shore (bank) of the Mississippi river. I am so lucky to be alive. On the way down, I thought I was dead," he said.

Minneapolis Fire Chief Jim Clack says divers went into the river, searching for possible survivors who had been trapped in vehicles. He says, after the first few hours, the likelihood of finding people still alive diminished. He says his teams shifted from rescue operations to body recovery operations.

"When we move from a rescue to recovery mode, you want to search every void space. When you have a collapse of freeway spans like this, there's a lot of void spaces that are hard to get into and we do not want to get into those spaces until it is safe to do so," he explained.

Chief Clack says officials are working closely with structural engineers to determine when and where it is safe for recovery crews to enter. As to why the bridge suddenly collapsed, Clack says investigators will start looking for clues, Thursday morning.

"Federal, state and city experts are going to be looking at this span of bridge to make that determination. It is way too early for us to speculate. It is a total collapse of a significant section of the freeway and so something went wrong and we are going to get to the bottom of what happened," he said.

Clack says this is by far the worst disaster he has seen in Minneapolis in the more than 20 years he has worked there. Minnesota Governor Tim Pawlenty called it "a catastrophe of historic proportions" for the whole state.

The eight-lane bridge, which passes near the University of Minnesota, near downtown Minneapolis, was the scene of some repair or road maintenance work at the time of the collapse, but there is no indication as to whether that played a role in the disaster. University of Minnesota School of Engineering inspectors had examined the bridge in 2001 and found no serious problems, although their report does mention signs of fatigue on a steel truss under the roadway.

The U.S. Department of Homeland Security says there is no indication that there was any sabotage of the structure.