Thousands of people have been evacuated from rising waters in North Dakota, US authorities said Friday, voicing fears some 30,000 could be left homeless by the state's worst floods in over a century.

As rising waters from the Red River began to breach levees and miles of sandbag dikes, volunteers battled freezing temperatures in a desperate bid to shore up flood barriers around Fargo, North Dakota.

The US Army Corps of Engineers said a levee holding back the swollen river had leaked, and earlier Friday authorities began evacuating around 150 homes from an area southeast of the city's water plant, the second mandatory evacuation zone established in a matter of hours.

An estimated 3,500 people have been evacuated so far. But many fear the worst is yet to come, with river levels expected to rise to a 112-year record of 43 feet (13.1 meters) by 1:00 pm (1800 GMT) on Saturday.

The floods marked US President Barack Obama's first weather crisis and his administration signaled it would not repeat the mistakes of his predecessor George W. Bush, who drew widespread outrage and condemnation for bungling the response to Hurricane Katrina in 2005, one of the deadliest natural disasters in US history.

Obama issued a federal disaster declaration for 34 counties and two Native American reservations as nearly the entire state remained under a major flood warning. The president also declared a state of emergency for parts of Minnesota, the state which shares a Red River border with North Dakota.

Homeland Security Secretary Janet Napolitano said the federal government was ready to house and feed 30,000 people for up to a week.

"In the worst case scenario we could be dealing with 80,000 to 100,000 people evacuated," Napolitano told reporters, adding the vast majority would likely stay with family or friends.

The Federal Emergency Management Agency (FEMA), which Napolitano oversees, announced it was providing massive commodities to evacuees, including over 170,000 prepackaged meals, 30,000 cots, 38,000 blankets, 50,000 hygiene kits, 66,043 gallons (250,000 liters) of water and 50 generators.

Several key federal agencies were coordinating their efforts with the Department of Health and Human Services. The Army Corps of Engineers, Coast Guard, Customs and Border Patrol, American Red Cross and Salvation Army were also providing logistical support.

Over 1,300 North Dakota National Guardsmen were filling sandbags, patrolling dikes and breaking ice jams.

Officials said several hospitals, clinics and area colleges were also evacuated.

"Right now we are going to focus on trying to save everything we have protected," said Fargo Mayor Dennis Walaker.

In the nearby city of Moorhead, Minnesota, National Guard troops and construction firms pitched in to ferry trucks full of sandbags to shore-up defenses against the floodwaters.

But efforts were hampered by cold weather.

Shari Lee, a 40-year-old hospital worker from Moorhead said fresh snowfall on Friday meant helpers had to wrestle with sand bags now stiff with ice and show.

Lee moved to the area in 1998 because it was unaffected by floods, which hit parts of the region a year earlier. She now faces the prospect of surrendering her home of 10 years to the flood waters.

"We thought the '97 flood was the flood of the century, so we thought we were safe," Lee said, gesturing to the pale green house behind her.

"We're not going under, but a lot of our neighbors are. That is just as hard."

Authorities said the Red River -- swollen with seasonal snow melt -- was approaching record levels, and showed no signs of abating.

"None of us, no matter how old we are, have ever seen this," Walaker said. "We are in uncharted territory."

Residents trapped in the area were rescued by boat and helicopter because crews feared bracing the increasingly menacing river, which runs along the North Dakota-Minnesota border and flows northward to Canada.

Fargo was most at risk because it has not developed the extensive flood protection systems of upriver cities such as Grand Forks and Winnipeg, Canada.

Nearby Casselton was preparing to open its doors for up to 1,500 evacuees. Several area high schools planned to do the same.

More snow was forecast to fall on the Red River valley in the coming days and rain could worsen flood conditions next week.

But for 52-year-old Dennis Sullivan, a lifelong resident of the Fargo-Moorhead area, giving up was not an option.

"We're holding our own," Sullivan called over flooded Elm Street in Moorhead. "We've fought a lot of floods, and they've never won. This one isn't going to either.

"We're here to stay," he said.