GRAND FORKS, N.D. (AP) _ Floodwaters surged over a dike Friday, swamping homes, an elementary school and a nursing home just hours after 2,000 people were roused from bed by warning sirens.

Fast-rising floodwaters chased another 400 people from their homes Friday night. Streets in the Central Park neighborhood filled within minutes, sending residents racing to their cars in a mad scramble to escape.

``We had no warning,'' said Phyllis Hart while trudging through knee-deep water outside her home, which had been dry only minutes before.

Grand Forks Mayor Pat Owens said the city of 50,000 people would fight against the rising Red River.

``We won't give up,'' she said. ``In the end, we hope to win.''

About 2,000 people, including 116 residents of a nursing home, were awakened by sirens before dawn and evacuated from four riverside areas before water surged over the dike protecting a park.

``It's like a waterfall coming over the dike,'' police Lt. Byron Sieber said.

It didn't take long before 300 homes were underwater, along with the nursing home and the school.

``Some of these houses out there _ it's just the roof sticking out now,'' Ms. Owens said.

About 3,000 people have been evacuated since Thursday and residents were told to be ready for flooded basements and streets. Classes were canceled at the University of North Dakota and students helped top off already towering sandbag dikes.

Weary flood fighters could barely keep up with water spilling over or through holes and cracks in other dikes. Hundreds of National Guardsmen and soldiers from Grand Forks Air Force Base were helping with sandbags.

Most residents of the Almonte Living Center were taken to an elementary school. Their wheelchairs filled the library as they watched flood coverage on a TV set up in front of a chalkboard with first-grade vocabulary words.

``This is the first time I've ever had this happen,'' said a 96-year-old resident, Trudy Nepper, who has lived in Grand Forks since 1925.

Vern Sander, 34, said he left his home Thursday with his wife and 16-month-old boy.

``I emptied my house and took what I needed,'' he said, seemingly resigned to losing his house. ``If it's going to happen, it's going to happen.''

Just across the Red River, in East Grand Forks, Minn., about 400 National Guardsmen were on their way to help 200 already on hand. Flash flooding on the south end of the city forced some people to evacuate, but officials did not immediately know how many left. Some dikes were failing.

``The flood is just testing us, I guess, as much as it possibly could,'' said Lynn Stauss, mayor of East Grand Forks. ``We put a sandbag down, you go away a few minutes, and it seems like the river has risen that much.''

The city ordered two helicopters to help with more evacuations, if needed.

Melting snow from a blizzard that pounded the state early this month is blamed for swelling rivers and spreading water across the flatlands of eastern North Dakota.

The National Weather Service raised its projected crest for the Red River in Grand Forks to 54 feet by late Saturday. Flood stage is 28 feet and the river stood at 52.6 feet by Friday night.

Grand Forks is about 75 miles north of Fargo, where the Red flooded a small neighborhood late Thursday after a dike broke there. Most dikes in Fargo appeared to be holding.

The National Weather Service said the river would remain at its predicted crest of 39.5 feet for as long as eight days.