But Clinton Not Ready to Concede

WASHINGTON (Reuters) - Barack Obama was on the brink of winning the Democratic presidential nomination on Tuesday, claiming the support of a steady parade of uncommitted delegates and pushing rival Hillary Clinton to the verge of defeat.

At least 20 superdelegates -- party officials free to back any candidate at the August nominating convention -- and 10 delegates pledged to former rival John Edwards announced their support of Obama, who would be the first black presidential nominee of a major U.S. political party.

That put Obama fewer than 15 delegates from the 2,118 he needs to face Republican John McCain in November. He could clinch the honor after polls close in the final two contests in Montana and South Dakota, which have 31 delegates at stake.

Facing defeat, Clinton told a conference call with New York members of Congress that she would be open to becoming Obama's vice presidential running mate.

But her campaign said she did not plan to concede to Obama at a rally in New York later on Tuesday.

"The nomination fight goes on until somebody gets the magic number and that isn't there today and that is not at all what Senator Clinton is going to talk about tonight," Clinton campaign chairman Terry McAuliffe told CNN.