NEW YORK (Reuters) - Support for U.S. Democratic presidential candidate Elizabeth Warren dropped nationally to its lowest level in four months, and nearly one in three potential Democratic primary voters say they do not know which candidate to pick with the first nominating contests less than two months away, according to a Reuters/Ipsos public opinion poll.

The poll, conducted on Wednesday and Thursday, found the level of indecision has jumped among of Democrats and Democratic-leaning independents after an already wide slate of candidates underwent a considerable amount of recent turnover ahead of the November 2020 election.

U.S. Senator Kamala Harris of California quit the race this week, and two new candidates, former New York City Mayor Michael Bloomberg and former Massachusetts Governor Deval Patrick, jumped in the race late last month.

The latest poll found that support declined for all of the top candidates, including Warren, when compared with a similar poll that ran on Nov. 20-22.

Support dropped by 2 percentage points for former Vice President Joe Biden to 19%. It fell by 3 points for U.S. Senator Bernie Sanders of Vermont to 14%, and it declined by 1 point to 6% for Mayor Pete Buttigieg of South Bend, Indiana.

Bloomberg, a billionaire media mogul, entered the race as the fifth-most popular candidate with 4% support.

Support for Warren dropped by 2 points to 9% in the national poll, the worst showing for the U.S. senator from Massachusetts in the Reuters/Ipsos poll since August.

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To be sure, Warren is still among the most popular candidates in Iowa, which will be holding its nominating contest on Feb. 3, and she is also among the top candidates in other early primary states. But nationally, Warren has slipped as her rivals for the nomination criticized her proposal for extending government-paid healthcare to all Americans as too costly.

Meantime, 31% of Democrats and independents said they “don’t know” which candidate to support. That is the highest level of indecision measured in Reuters/Ipsos poll dating back to mid-April.

The Reuters/Ipsos poll was conducted online, in English, throughout the United States. It gathered responses from 719 adults who identify as Democrats, independents and politically unaffiliated. The poll has a credibility interval, a measure of precision, of 4 percentage points.

Click here for the poll results: tmsnrt.rs/2RobVKh