Barge hits Mississippi River bridge at St. Louis

The U.S. Coast Guard is investigating why a barge hit a Mississippi River bridge at St. Louis, causing four barges to briefly break free but leaving no apparent structural damage to the span.

Officials say the accident involving the Martin Luther King Bridge and the barge operated by Marquette Transportation happened shortly after 2:00 a.m. Monday.

A bridge pier was hit. And though officials say the bridge sustained no significant damage and was open to morning commuters between St. Louis and southwestern Illinois, engineers planned to inspect the bridge later Monday.