Ending her defiance, Hillary Clinton has finally decided to endorse her rival Barack Obama on Saturday after an unsuccessful, 17-month-old vigorous bid for the Democratic presidential nomination while aides indicated she could be eyeing the vice-president's slot.

"Senator Clinton will be hosting an event in Washington, DC, to thank her supporters and express her support for Senator Obama and party unity. The event will be held on Saturday," Clinton campaign official Howard Wolfson told reporters.

The 60-year-old former first lady's decision to formally end the campaign comes at the urging of senior party leaders who want the party to go into the Denver contention in August to elect a nominee unified after Obama on Tuesday night secured the 2,118 delegates to become the first African-American to clinch the nomination.

Media reports, which were not confirmed by her campaign, said she has privately told the party leaders that she is prepared to accept the number two slot but Obama, with whom she had a brief talk on Tuesday, did not give his mind.

He appointed a three-person committee headed by Caroline Kennedy, daughter of the slain charismatic US president John F Kennedy, to search for the vice president or his running mate.

His advisers are evaluating pro and cons of putting Clinton on the ticket, but there is formidable opposition to the move among them.

Wolfson statement that she would express support for Obama and call for party unity will set at rest speculation that she might challenge Obama's nomination at the credential meeting in July.