Obama says "change has come to America"

CHICAGO (Reuters) - President-elect Barack Obama told cheering supporters on Tuesday "change has come to America" and called on Americans to back a spirit of unity to attack the country's pressing challenges.

Obama congratulated defeated Republican John McCain for the long, hard campaign that he fought. He called on Americans to support a "new spirit of sacrifice."

"The road ahead will be long. Our climb will be steep. We may not get there in one year or even one term, but America, I have never been more hopeful than I am tonight that we will get there," he said.