Officials in the upper Midwestern U.S. city of Minneapolis, Minnesota say river conditions are getting worse as they continue their search for victims of Wednesday's collapse of a major highway bridge.

The number of confirmed dead stands at five, after a body was pulled from the water late Thursday.  Rescuers are fighting a strong current as they search for other victims in murky water filled with wreckage.

It is not clear how many people are still missing.  Hennepin County Sheriff Richard Stanek has estimated that eight people are still unaccounted for, but he told reporters that estimate is "very fluid."

Hospital officials say at least 79 people were injured during the evening rush-hour accident Wednesday, when a large portion of the bridge, packed with cars, broke apart and plunged 20 meters into the Mississippi River.

President Bush's wife, Laura, examined the wreckage today during a previously scheduled visit to Minneapolis.  The president himself will visit the site on Saturday to be briefed by local officials.

Federal transportation officials have pledged $5 million to the state of Minnesota for cleanup and recovery efforts. 

The eight-lane bridge was built in 1967.  State transportation officials were warned as early as 1990 that the bridge was "structurally deficient," meaning it was in need of major repair or even replacement.  It received the same designation after a federal inspection in 2005, but state engineers say it was not slated to be replaced until 2020.

A state inspection last year discovered numerous deficiencies with the bridge, but transportation officials elected to make frequent inspections rather than badly needed repairs.

The National Transportation Safety Board has sent a team of investigators to probe the disaster.  Minnesota Governor Tim Pawlenty says the state will conduct its own investigation. 

Some information for this report was provided by AFP, AP and Reuters.