Six hundred residents in southwest Iowa have been told to evacuate their homes after a levee was breached across the border in Missouri.

Iowa Department of Homeland Security spokeswoman Stefanie Bond says the evacuation ordered Sunday morning covers half of the town of Hamburg. Residents are being told to get out within 24 hours.

The U.S. Army Corps of Engineers reports a levee was breached Sunday south of Hamburg in Atchison County, Mo. The corps couldn't immediately provide more details.

Bond says there wasn't a full breach, and the evacuations upstream from the levee are a precaution. Bond describes the water coming through as being between the spray of a garden hose and a fire hose.

But Fremont County emergency coordinator Mike Crecelius says the situation is very unstable.