Washington (CNN) A new national poll finds former Vice President Joe Biden holding a comfortable lead over the rest of the Democratic field, but a separate survey of early voting states shows a closer contest between Biden and his two top progressive challengers.

Biden continues to lead in the race with 27% among Democrats and Democrat-leaning independents, according to an ABC News/Washington Post poll released on Sunday. Vermont Sen. Bernie Sanders comes in second at 19%, down slightly from 23% in July, while Massachusetts Sen. Elizabeth Warren gained 6 points from July to come in third at 17%. California Sen. Kamala Harris saw her support drop to 7% after polling at 11% in July, and South Bend, Indiana, Mayor Pete Buttigieg rounds out the top five at 4%.

The new poll again demonstrates Biden's dominance over the rest of the Democratic pack nationwide, though a CBS News and YouGov survey among likely Democratic voters in early voting states finds Biden in a tight matchup against Warren and Sanders, who have galvanized the party's progressive base.

In that poll, also released Sunday, Biden is neck and neck with either Warren and Sanders in Iowa, New Hampshire and Nevada. The only early voting state in which he holds a sizable lead, South Carolina, finds him at 43% over Sanders' 18% and Warren's 14%, a reflection of his strong support among African-Americans.

Among 18 states that will hold primaries or caucuses early in 2020, including those on Super Tuesday, Warren stands at 26% about even with Biden at 25%, with Sanders in third place at 19%. Harris trails behind with 8% along with Buttigieg (6%) and former Texas Rep. Beto O'Rourke (4%). Former Housing and Urban Development Secretary Julián Castro and New Jersey Sen. Cory Booker each have 2% support across these states, with the rest of the Democratic field at 1% or less.

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