Worker walks past vehicles sitting on bridge that collapsed over Mississippi River during evening rush hour on 1 August (02 Aug 2007)

Emergency crews in the northern U.S. city of Minneapolis, Minnesota, resumed their search Friday for more victims of this week's deadly collapse of a major highway bridge.

A large portion of the bridge broke apart Wednesday and plunged 20 meters into the Mississippi River. Officials say strong river currents are making it difficult for crews searching for victims believed to be trapped in the wreckage. Five people have been confirmed dead. Various reports say between eight and 30 people are missing. Hospital officials say at least 79 people were injured in the bridge collapse.

President Bush's wife Laura will examine the wreckage Friday during a previously scheduled visit to Minneapolis. The president himself will visit the site on Saturday.

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 hold its own investigation.