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(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’$2 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.

The CBS News/YouGov survey also is notable for finding billionaire hedge fund founder Tom Steyer with 2% support in Nevada, helping him qualify for the October Democratic debate.

The Biden campaign in recent days has sought to tamp down expectations for his performance in Iowa, with senior campaign aides saying the former vice president could afford to lose the Hawkeye State and still capture the nomination.

“Do we think we have to win Iowa? No. Do we want to win Iowa? Yes, we do,” a senior campaign aide said Tuesday. “We think we’re going to win; we know it’s going to be a dogfight. The same thing is true in New Hampshire.”

The ABC News/Washington Post poll was conducted by phone from September 2 to September 5 in English and Spanish among a random national sample of 1,003 adults. The results have a margin of sampling error of 5.5 points, including a sample of 437 Democrats and Democratic-leaning independents.

The CBS News and YouGov survey was conducted from August 28 to September 4 among a sample of 16,525 registered voters from 18 states that will hold primaries or caucuses in February and early March: Alabama, Arkansas, California, Colorado, Iowa, Maine, Massachusetts, Minnesota, Nevada, New Hampshire, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Utah, Vermont and Virginia. The sample includes 7,804 self-identified Democrats and Democratic-leaning independents and the combined results have a margin of error of plus or minus 1.8 points.

CNN’s Jennifer Agiesta contributed to this report.