DES MOINES, Iowa – Sen. Elizabeth Warren of Massachusetts is the new Iowa polling leader, narrowly in first place ahead of former Vice President Joe Biden, according to a new poll of the state from The Des Moines Register and CNN.

The poll showed that Warren was the first choice for 22% of would-be Democratic caucusgoers, an increase of 6% from the 15% support she held in June, when The Register last polled the state. Biden dropped from a first-place June showing of 24% to 20%. The result left the two in a statistical tie, well ahead of the rest of the pack.

The poll is the latest evidence of Warren’s political rise in the 2020 race. Her campaign stops have become bona fide events, with 20,000 people attending a speech in Manhattan this week and 2,000 turning out in Iowa City on Thursday night.

Sen. Bernie Sanders of Vermont placed third with 11%, the second consecutive poll from The Register in which his campaign has seen precipitous decreases in support. Sanders, who placed in a statistical tie with Hillary Clinton in the state’s 2016 contest, had 25% support in the paper’s March poll and 16% support in June.

Mayor Pete Buttigieg of South Bend, Indiana, placed fourth in the Register’s poll, with 9%. He had 14% in the Register’s June poll and has fallen in other surveys of the state since then before launching a television advertising campaign here after Labor Day.

The gains by Warren come largely at the expense of Sanders. His polling drop-off comes as his campaign has reordered staff in early nominating states in an effort to reboot his campaign.

Sen. Kamala Harris of California was fifth overall with 6% support. Sens. Cory Booker of New Jersey and Amy Klobuchar of Minnesota each had 3% support. Four candidates were the first choice of 2% of likely Iowa caucusgoers.

The dynamics are far from set: Just one in five likely Democratic caucusgoers said their minds were made up, and 63% said they could still be persuaded to support a different candidate.