ST. LOUIS (AP) - The Army Corps of Engineers is monitoring a major Mississippi River levee near St. Louis after discovering a problem that could cause the levee to fail.

Corps officials say the Wood River Levee is not in imminent danger, but the problem is urgent and needs to be fixed. A repair plan and cost estimate have not been determined.

The levee protects the Illinois communities of Alton, East Alton and Wood River. Corps officials met Wednesday with local leaders.

The corps says ``sand boils'' were discovered near the Melvin Price Locks and Dam. Sand boils occur when river water on the outside of the levee creates enough hydrostatic pressure to push soil, and water, to the surface on the inside. Eventually, the flow can erode the levee foundation and eventually cause failure.