In a sign of the slugfest that the contest for the Democratic presidential nomination could become, Sen. Bernie Sanders went after former vice president Joe Biden on the matter of US trade deals during a TV appearance.

Biden and Sanders right now often are ranked as the top two front-runners in a crowded, 20-candidate race for the Democratic nomination.

“Well, look, I’m running against, I think, 19 other people, so I’m concerned about everybody. But I think when people take a look at my record versus vice president Biden’s record, I helped lead the fight against NAFTA,” Sanders said. “He voted for NAFTA. I helped lead the fight against [Permanent National Trade Relations] with China. He voted for it. I strongly opposed the Trans-Pacific Partnership. He supported it. I voted against the war in Iraq. He voted for it.

“So I think what I hope, Anderson, what this campaign is about — and I have to tell you, I like Joe Biden. Joe is a friend of mine,” Sanders added. “But I think what we need to do with all of the candidates, have an issue-oriented campaign, not personal attacks, but talk about what we have done in our political lives, what we want to do as president, and how we’re going to transform our economy so that it works for all of us and not just the 1 Percent.”

NAFTA is the North American trade zone negotiated under the George HW Bush administration and carried forward and approved by Congress with support by the Clinton administration. Permanent Most Favored Trade status improved China’s trade status with the United States toward the end of the Clinton administration. The Trans-Pacific Partnership is a Pacific-area trade zone negotiated by the Obama administration but cancelled by the Trump administration.

Sanders also reacted to tweets from Donald Trump encouraging Sanders to become angry with the Democratic National Committee over Trump’s allegation–made without evidence–that the DNC was rigging the nomination against Sanders, and for, Biden.

“I think most of us don’t know what the president is usually talking about, but our response to that Anderson was, yeah, I do feel indignation and anger against a president who told the American people — you remember this — he would provide health care to everybody and yet he worked overtime to try to throw 32 million Americans off of the health care that they have,” Sanders said. “He was a president, a candidate who said he would not cut Social Security, Medicare and Medicaid, then he brings forth a budget with massive cuts to Medicaid, Medicare and cuts to Social Security as well. So our indignation is at a president who lied to the working families of this country when he said he would stand up for them.”