Democratic presidential candidate Joe Biden gained two more endorsements from onetime backers of rival Kamala Harris' campaign, a sign of early strength in consolidating support after the U.S. senator left the race.

Biden's campaign on Thursday announced the endorsement of two former mayors of Dover, New Hampshire, Jack Buckley and William Boc, who had supported Harris. New Hampshire hosts Democrats' second presidential nominating contest in February.

Harris, who would have been the first woman and second black U.S. president, withdrew from the race on Dec. 3, as her support flagged and she lacked the money to go on.

Her departure touched off a race to secure support she had won from elected officials and donors.

One Biden aide who asked not to be named to speak openly said every campaign is working hard to attract her supporters and that Biden's campaign long felt they could appeal to some Harris followers.

Still, many key Harris supporters, including California Governor Gavin Newsom, have made no choice yet. Former Harris supporter and San Jose, California, Mayor Sam Liccardo backed ex-New York City Mayor Mike Bloomberg's bid for the White House on Monday.

And not all voters will move from Harris to Biden. Harris was more likely to be listed as a second-choice for voters favoring U.S. Senator Elizabeth Warren and South Bend, Indiana, Mayor Pete Buttigieg than Biden in an Iowa State University poll last month of people likely to attend Iowa's first-in-the-nation Democratic caucus.

Within days of Harris dropping out, however, Biden's campaign can claim progress. Former Harris supporters now with Biden include former Richland County, South Carolina, Council Chair Bernice Scott and six others from the senator's home state of California, including Assembly member Autumn Burke, Assembly Democratic Caucus Chair Mike Gipson and Democratic National Committee (DNC) member Bob Mulholland.

Biden is eager to claim front-runner status in a race against 14 Democratic rivals hoping to face Republican President Donald Trump in the November 2020 election.

A day after Harris ended her bid, Biden told reporters he would consider her as a potential running mate even though the two had clashed during a debate earlier this year.

Mulholland said several campaigns sought his support but he decided to go with a safe choice after knowing Harris would face an uphill battle against better-known candidates.

"I saw Harris as courageous for making the effort," he said. "Joe is solid and pragmatic."

(Reporting by Trevor Hunnicutt; Additional reporting by James Oliphant; Editing by Cynthia Osterman)