Thousands of people have been asked to evacuate their homes in the US Midwest as the swollen Red River reaches its highest levels for 112 years.

Rising waters have breached a dyke in Fargo, North Dakota, where about 400 people have already left their homes. And officials in neighbouring Moorhead want 2,660 homes evacuated.

On Friday the river swelled to previously unseen heights, surpassing the record of 40.1 feet set in 1897 in Fargo.

Amid fears that Moorhead and Fargo could be deluged, US president Barack Obama sent Nancy Ward, acting head of the Federal Emergency Management Agency, to oversee the towns' preparations.

The president issued a federal disaster declaration for parts of Minnesota and the entire state of North Dakota earlier last week.