Former Vice President Joe Biden Joe BidenFormer Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick Bloomberg rolls out M ad buy to boost Biden in Florida MORE has widened his lead among fellow 2020 Democrats, with a new poll showing him atop the crowded field by double digits.

Twenty-nine percent of Democratic and Democratic-leaning registered voters said they supported Biden in the CNN poll released early Tuesday. Sen. Bernie Sanders Bernie SandersSirota reacts to report of harassment, doxing by Harris supporters Republicans not immune to the malady that hobbled Democrats The Hill's Morning Report - Sponsored by Facebook - Republicans lawmakers rebuke Trump on election MORE (I-Vt.) has 15 percent and Sen. Elizabeth Warren Elizabeth WarrenOvernight Defense: Appeals court revives House lawsuit against military funding for border wall | Dems push for limits on transferring military gear to police | Lawmakers ask for IG probe into Pentagon's use of COVID-19 funds On The Money: Half of states deplete funds for Trump's 0 unemployment expansion | EU appealing ruling in Apple tax case | House Democrats include more aid for airlines in coronavirus package Warren, Khanna request IG investigation into Pentagon's use of coronavirus funds MORE (D-Mass.) is at 14 percent, according to CNN.

Biden’s support has risen 7 points since a survey conducted in late June, with no other candidate making significant improvements in polling numbers, CNN noted.

Biden’s supporters are more often self-identified Democrats than independents, older rather than younger, and are moderate and conservative voters instead of liberals, pollsters found.

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Thirty-one percent of self-identified Democrats, 34 percent of voters ages 45 and older, and 34 percent of moderate and conservative voters back Biden, according to the poll.

Biden’s support also comes from the 54 percent of Democratic and Democratic-leaning registered voters whose main goal is to boot President Trump Donald John TrumpFederal prosecutor speaks out, says Barr 'has brought shame' on Justice Dept. Former Pence aide: White House staffers discussed Trump refusing to leave office Progressive group buys domain name of Trump's No. 1 Supreme Court pick MORE from office in 2020, with 35 percent of individuals in that group supporting the former vice president.

While Biden’s support has increased, Sen. Kamala Harris Kamala HarrisTexas Democratic official urges Biden to visit state: 'I thought he had his own plane' The Hill's Campaign Report: Biden on Trump: 'He'll leave' l GOP laywers brush off Trump's election remarks l Obama's endorsements A game theorist's advice to President Trump on filling the Supreme Court seat MORE (D-Calif.) has seen a notable decline in support, with 5 percent of potential Democratic voters backing the senator, compared to 17 percent in the June poll, which was conducted soon after the first round of Democratic presidential primary debates. Harris and Biden clashed during the first round of debates, with the California senator challenging Biden on his views on busing.

The new poll was conducted from Aug. 15 to Aug. 18 and surveyed 1,001 adult registered voters. It has a margin of error of 3.7 percentage points.