Washington - The complete flooding of the small US town of Winfield, Missouri, was prevented when the town's inhabitants hurriedly created a secondary dam out of sandbags after another of the many levees holding back the Mississippi River broke, local media reported Saturday.

On Friday, the US National Weather Service had issued a flash flood warning for the town of about 900 residents as the levee broke.

More than two dozen levees have been breached by flood waters along the vast river system, sending millions of litres into towns and prime agricultural land across the US Midwest, according to the US Army Corps of Engineers, which maintains the system.

Before the latest breach, most of the community's 100 houses had already been evacuated, and part of the area is standing under water. No further breaches however are expected, according to US media reports.

Two people were killed in the US state of Iowa when a tree over turned in a storm, crushing their car.

About two dozen people have died as a result of the floods.

Extensive flooding earlier in June had already destroyed property and farmland across the heavily agricultural state of Iowa, contributing to an ongoing surge in food prices.

Water from those floods along tributaries to the Mississippi River has surged downstream. (dpa)