Massachusetts Senator Elizabeth Warren tops the field for the 2020 Democratic presidential nomination in a new poll, though other voter surveys have former vice president Joe Biden on top.
The 70-year-old Warren was backed by 28 percent of Democratic and Democratic-leaning independent voters in a poll published on Thursday by Quinnipiac University.
The 76-year-old Biden, who has topped most polls since joining the White House race, received 21 percent.
Vermont Senator Bernie Sanders, who recently suffered a heart attack, was at 15 percent in the Quinnipiac survey while Pete Buttigieg, the mayor of South Bend, Indiana, was at 10 percent.
California Senator Kamala Harris received five percent while Minnesota Senator Amy Klobuchar was at three percent.
While Warren topped the Quinnipiac poll, Biden came out ahead in a CNN survey published on Wednesday which was conducted by SSRS, an independent research company.
Biden was the choice of 34 percent of Democratic and Democratic-leaning registered voters in the CNN poll while 19 percent opted for Warren and 16 percent for Sanders.
Buttigieg and Harris each received six percent while Klobuchar was at three percent.
Warren has vied with Sanders for the progressive vote with bold ideas on health care and education, while Biden has campaigned as an experienced moderate who has the best chance of defeating Republican Donald Trump in the November 2020 White House race.
Biden has been the frontrunner in the crowded Democratic field longer, but Warren has been surging lately and drawing large crowds to her campaign rallies.
Biden has also been caught up in the political turmoil surrounding Trump, accused of pressing Ukraine for damaging information on the former vice president and his son, Hunter Biden, who served on the board of a Ukrainian gas company.
Democrats in the House of Representatives have opened an impeachment inquiry into Trump for abuse of power.
The Quinnipiac poll of 713 Democratic voters and independent voters who lean Democratic has a margin of error of plus or minus 4.6 percentage points.
The CNN poll of 424 registered voters who are Democrats or Democratic-leaning independents has a margin of error of plus or minus 5.8 percentage points.
