Minneapolis Fire Chief Jim Clack said at a news conference seven deaths had been confirmed but the number was expected to rise. He said more than 60 people were sent to hospitals. At least six were in critical condition, a medical official said.

"We've moved from a rescue mode ... to a recovery mode," Clack said, noting dive teams had been pulled from the river because of darkness.

A city emergency official said about 50 vehicles had been thrown from the Interstate 35W bridge into the water.

"It's a catastrophe of historic proportions for Minnesota," Gov. Tim Pawlenty said.

The 40-year-old span had a "somewhat unique" design, Pawlenty said, but had been inspected in 2005 and 2006 with no structural deficiencies found. The bridge was having non-structural concrete, guardrail and lighting work done this summer.

One man said he saw about 60 children on a school bus perched on a bridge section above the water "yelling, screaming, bleeding and I believe some had broken bones." They were rescued.