(CNN) Massachusetts Sen. Elizabeth Warren and former Vice President Joe Biden lead the crowded Democratic primary field, with 28% and 25% support each from likely Democratic voters, according to a Monmouth University national poll out Wednesday.

Warren and Biden are followed by Vermont Sen. Bernie Sanders with 15%, California Sen. Kamala Harris and South Bend, Indiana, Mayor Pete Buttigieg at 5% each, and businessman Andrew Yang and author Marianne Williamson with 2%. No one else received over 1% in the poll.

Patrick Murray, Monmouth University's polling director, acknowledged that their August poll -- which found Warren, Sanders, and Biden in a three-way tie -- was an outlier compared with other polling conducted around the same time. But the new Monmouth poll confirms other recent polling suggesting a far tighter race for the Democratic nomination.

It, along with a late-September Quinnipiac University poll , is the second recent national poll to show Warren and Biden topping the field and within the margin of error of each other, and the third to show Warren in the mid- to upper-20s in support.

While eight in 10 registered Republicans and Republican-leaning independent voters say Donald Trump ought to be re-elected President in 2020, 15% said someone else should be in office.

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