Washington  - The waters overwhelming North Dakota's largest metropolitan area appeared to have reached their peak on Saturday after prompting thousands to evacuate.

The Red River in Fargo and the neighbouring city of Moorhead had crested at 12.4 metres and dropped extremely slightly one day earlier than expected, breaking the record set in 1897 and surpassing severe flooding 100 years later in 1997, the National Weather Service said.

More than 10,000 residents of North Dakota's largest metropolitan area evacuated Friday.

Forecasters warned however the water level will remain high for many days and could yet rise again up to a third of a metre. Cold weather appeared to have slowed runoff into the river.

US President Barack Obama on Saturday pledged continuing national support to victims of severe flooding in North Dakota and neighbouring Minnesota and South Dakota.

In his weekly radio address, Obama also praised the thousands of volunteers who have filled sandbags to fight the rising waters.

"Even as we face an economic crisis which demands our constant - focus, forces of nature can also intervene in ways that create other crises to which we must respond - and respond urgently," he said. "For the people of North and South Dakota and Minnesota who live along rivers spilling over their banks, this is one such moment."

Obama said federal officials were working with governors in each state to offer assistance. The Department of Homeland Security and the Federal Emergency Management Agency were coordinating Washington's response. (dpa)