The 2020 presidential candidate joined several others campaigning for the Democratic nomination on Friday in Iowa, and the California senator had some harsh criticism for one of the current front-runners, Massachusetts Senator Elizabeth Warren, regarding the latter’s connections to corporations.

“We’re all here to fight to end that national nightmare called Donald Trump. And to win, Democrats. To win,” Harris said during her speech at the Iowa Democratic Party’s Liberty And Justice Dinner.

Harris added that in order to win the 2020 election, Democrats need a candidate who can “go toe to toe” with President Donald Trump, and that she is that person.

“To win, we are going to have to fight against those who have been trying to push hate and division among us and have Americans turn on each other. To win, we’re going to have to fight for what I know in my heart and in my soul to be true—which is in the beauty and the diversity of who we are as a nation. We all have so much more in common than what separates us,” Harris said.

Harris then highlighted her qualifications, including her time serving as California’s attorney general.

“I’ve only had one client in my entire life, and that has been the people. Unlike other people, unlike others, I have never represented a corporation,” Harris said, alluding to Warren’s previous work as a lawyer for several large corporations. “I have never represented a special interest. I started my career fighting for the people. In fact, the first time I walked into a courtroom, I spoke five words. ‘Kamala Harris, For the People.’”

Warren’s connections to corporations have been a frequent problem for her campaign and were highlighted earlier this week in a report from The New York Times. The article included Warren’s work on behalf of LTV Steel, who she represented in 1995 by petitioning the Supreme Court to hear the lawsuit. According to the suit, LTV Steel filed for bankruptcy in 1986, but a law enacted in the 1990s required the company to contribute to a health care fund for retired workers in its coal mines. In the suit, the company said they should not be liable due to the Chapter 11 filing.