"It's going to take a long time for the community to recover, and so we will help in any way we can," Bush said outside St. John's Church, across from the White House, where he and first lady Laura Bush attended a worship service.
A tornado that killed at least eight people in Greensburg was one of many twisters that touched down in six southwest Kansas counties. Numerous other tornadoes were reported in the Plains from South Dakota south into Oklahoma.
"Our hearts are heavy for the loss of life in Greensburg, Kansas," Bush said about the tornado that demolished 95 percent of the town. "It just basically wiped it out."
The president has declared parts of Kansas a disaster area, freeing up federal money to aid in recovery.
"There's a certain spirit in the Midwest of our country -- a pioneer spirit that still exists, and I'm confident this community will be rebuilt," Bush said. "To the extent that we can help, we will.
"The most important thing now, though, is for our citizens to ask for the good Lord to comfort those who hurt."