WASHINGTON, June 5 (Xinhua) -- U.S. senator Hillary Clinton will end her bid for the White House Saturday, although the precise nature of her departure from the contest is unclear, local media reported Thursday.

    It could be unconditional or just a suspension of her campaign.

    The Washington Post said Clinton is "likely to suspend her presidential campaign on Saturday and endorse her rival senator Barack Obama."

    ABC News reported that pressure is "mounting on Clinton to concede, especially from her supporters in Congress who went out on a limb for her, and are anxiously waiting to endorse Obama."

    The New York Times said that Clinton spokesman Howard Wolfson and other aides said she would express support for Obama and party unity at an event in Washington that day.

    One adviser said Clinton would concede defeat, congratulate Obama and proclaim him the party's nominee, while pledging to do what was needed to assure his victory in November.

    Meanwhile, Clinton and her supporters started efforts to win the vice presidential nomination, but media reports suggest the aggressive effort could backfire.

    Asked about the issue, Obama wouldn't shed any light on it.

    On NBC Nightly News, Obama said, "We have just completed a very hard fought contest. I think she needs to catch her breath. I need to catch mine. I think all our supporters need to just sit back and let things sink in."

    On the CBS Evening News, he said it is "premature" to touch upon the issue.

    In addition, Obama's campaign announced the vetting of potential running mates was to be managed by a three-person team of one-time first daughter Caroline Kennedy, former Deputy Attorney General Eric Holder and Washington insider Jim Johnson.

    Obama clinched the Democratic nomination Tuesday night, becoming the first African American presidential nominee of a major U.S. political party.