U.S. Sen. Kamala Harris on Wednesday called President Donald Trump "a predator" while speaking to potential caucusgoers at a picnic in Iowa.

The Democratic presidential candidate used the term during an event for Iowa Democrats in West Des Moines, signifying one of her most pointed criticisms to date of the president. The former California attorney general repeated the line hours later at a town hall in Des Moines.

"I prosecuted the big banks when they preyed on homeowners. I've prosecuted the pharmaceutical companies when they preyed on seniors. I have prosecuted transnational criminal organizations when they preyed on women and children," Harris said in West Des Moines. "I know predators. And we have a predator living in the White House."

The line drew loud applause.

"Donald Trump has predatory nature and predatory instincts," she continued. "And the thing about predators … is that they prey on the vulnerable. They prey on those who they do not believe are strong. And the thing about predators, you must … most importantly know, predators are cowards."

Harris later spoke to the Des Moines Register about her decision to describe the president that way.

"I've been thinking it," she said. "… You look about the instincts and the nature in how he has conducted himself. That is my conclusion."

Aaron Brit, a spokesman for the Republican Party of Iowa, criticized Harris' comments in a statement.

"Kamala Harris is clearly so embarrassed by her own record of prosecuting predators that she's lashing out at President Trump," Brit said. "2020 Democrats are so desperate that they are willing to resort to cheap hits to tear down this president, despite the fact that President Trump has made it clear time and again that he loves this country and all Americans — this year's Independence Day celebration in Washington will be the ultimate reflection of this fact."

Harris' remarks resonated with Sen. Claire Celsi, a Des Moines Democrat who attended the West Des Moines picnic. Celsi has not endorsed a candidate.

"I think she's speaking the truth," Celsi said of Harris' criticism of Trump. "I'm all for that. Speaking the truth is important."

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Erin Lain, 34, a law professor at Drake University, attended Harris' town hall in Des Moines. Lain is undecided on which candidate she will caucus for, but she really likes what she described as Harris' practically. Lain is particularly impressed with Harris' policy ideas to address the gender pay gap and protect reproductive health care, issues which Harris brought up during the town hall.

"I think she can really work with a lot of different groups to get things done," Lain said of Harris.

Harris was in Iowa less than a week after she participated in the second night of Democratic presidential debates in Miami. Her televised exchange with Joe Biden — in which she challenged the former vice president over his work with segregationist senators and his opposition of busing to integrate schools in the 1970s — is considered among the top moments of the two-night, 20-candidate event.

The Harris campaign reported that in the 24 hours after the second debate began, it raised more than $2 million online from more than 60,000 people.

The post-debate bump for Harris has also come into focus in polling. A new Suffolk University/USA TODAY Poll, conducted after the debate, shows Harris in second place among the crowded field, behind only Biden. The poll has a margin of error of plus or minus 4.4 percentage points.

In early June, before the debates, a Des Moines Register/Mediacom/CNN Iowa Poll showed Harris polling behind Biden, Sens. Bernie Sanders of Vermont and Elizabeth Warren of Massachusetts, and South Bend, Indiana, Mayor Pete Buttigieg.

That poll, which had a margin of error of plus or minus 4 percentage points, showed Harris and Warren tied for being named most often as respondents’ second choice for president.

Harris acknowledged her climb in recent polling to reporters, but she said there's still more work to do.

"I think that the only poll that really matters is on Election Day. But the fact that we are seeing momentum grow across the country is something that I'm very proud of," she said. "We have a great team on the ground here in Iowa and around the country."

Wednesday marked the start of a three-day swing for Harris through Iowa. It will include a house party in Indianola on Thursday, followed by a Fourth of July barbecue in Council Bluffs. She'll hold a town hall in Sioux City on Friday.

Barbara Rodriguez covers the Iowa Statehouse and politics for the Register. She can be reached by email at bcrodriguez@registermedia.com or by phone at 646-385-1212.