Democratic 2020 U.S. presidential candidate former South Bend, Indiana Mayor Pete Buttigieg attends a campaign event in Raleigh, North Carolina, U.S., February 29, 2020. REUTERS/Eric Thayer

WASHINGTON (Reuters) - Former South Bend, Indiana, Mayor Pete Buttigieg plans to endorse Joe Biden in the Democratic presidential nominating contest on Monday, shortly after ending his own bid for the White House, a top Buttigieg adviser told Reuters.

The boost to Biden comes along with an endorsement from outgoing rival Amy Klobuchar, a day before 14 states vote on Super Tuesday, in an apparent bid to consolidate support behind Biden and stop U.S. Senator Bernie Sanders.