Updated

The Mississippi River remains closed as authorities work to determine whether a sunken barge was a navigation hazard.

The Coast Guard closed the river Sunday after the old U.S. Highway 80 railroad bridge was struck by barges that broke free from a string under tow.

About 30 barges broke free and at least one sank. The Coast Guard says three others had been nudged against the river bank and the remaining barges have been rounded up.

The barges were being pushed by the boat Captain Buck Lay, which the Coast Guard says is owned by Memco Barge Line Inc.