History is being made.

Barack Obama has clinched the Democratic nomination for president, becoming the first African-American in the US history to lead a major-party ticket, the CNN said.

Senator Obama will declare himself the Democratic presidential nominee in a long-time-coming victory speech while reaching out to defeated rival Hillary Rodham Clinton, according to his campaign.

"Tonight, I can stand before you and say that I will be the Democratic nominee for President of the United States," he is expected to say.

The Illinois senator defeated the former first lady and one-time campaign front-runner Clinton in a 17-month

Clinton does not plan to concede the race, campaign chairman Terry McAuliffe told CNN -- but one of her leading supporters said "a moment of truth" was at hand.

"I think a decision has to be made about whether keeping this nomination wide open is in the best interest of winning in November," said Sen Dianne Feinstein, D-California.

"I do not believe that it is, and I'm a very strong supporter of Hillary being placed on ticket as a vice-presidential candidate," Feinstein said.