River traffic on the upper reaches of the Mississippi River, a vital waterway for moving billions of dollars worth of commodities, was halted late on Wednesday after a highway bridge collapsed in Minneapolis.
At least six people were killed and dozens injured when the 40-year-old bridge packed with vehicles in rush-hour traffic buckled and collapsed into the Mississippi River.
A spokesman for the U.S. Coast Guard in St. Louis said 5 miles (8 km) of the river on either side of the collapsed bridge had been shut to river traffic.
Barges laden with thousands of bushels of corn, soybeans and wheat ply the entire length of the Mississippi River from Minnesota to Louisiana, transporting the grains from production centers to export terminals at the Gulf Coast.
The flow of corn and soybeans this time of year is relatively slow as the crops will not be harvested until September, while supplies held over from last year run low.
The United States is the world's largest exporter of corn, soybeans and wheat, with the supplies shipped across the globe from Indonesia to Brazil to Spain.
Mark Davidson, spokesman for the U.S. Army Corps of Engineers in St. Paul district, said a lock and dam near the collapsed bridge had been closed, halting river traffic in the area.
"At this time due to the emergency, the lock and dam at lower St. Anthony's falls is closed," he said. He said there was not much movement of commodities this time of the year in that part of the Mississippi River.