Hillary Clinton visited Democrats on Capitol Hill Tuesday, stopping by the weekly Senate caucus lunch to address her former colleagues, including the man who has emerged as her main competitor: Sen. Bernie Sanders.

But Sanders left the lunch early and made his way straight to a press conference at the Capitol. He began by welcoming Clinton back to the Senate, and said he looked forward to a serious debate between the two of them on the issues, reiterating his oft-made point that he doesn’t run negative campaign ads. He proceeded to describe the differences between himself and the former secretary of state. Again and again, he talked up his positions on a variety of issues, and each time, he criticized Clinton for her positions, or, as he said, lack thereof.

On trade, Sanders said he opposed the major deals that have come through Congress in the previous three decades, from NAFTA in the 1990s to the TPP deal currently being negotiated, arguing they’ve have been bad for American workers.

“Secretary Clinton, I believe, has a different view on that issue,” he said.

Sanders then brought up his vote against the Iraq war when he was in the House of Representatives. Clinton voted for that war in 2002, an issue that hurt her in the 2008 presidential election against President Obama. Sanders also brought up his vote against the Patriot Act, which Clinton voted for as a senator.

Climate change was next. Sanders talked about his opposition to the Keystone XL Pipeline, saying Clinton “has not been clear on her views on that issue.”

Sanders also discussed Wall Street regulation and reform, calling for a return of Glass-Steagall regulations on big banks and saying that there is too much concentration of wealth and ownership. Clinton has, in the past, taken criticism for being too friendly toward Wall Street.

“To the best of my knowledge, those are ideas that Secretary Clinton does not agree with,” Sanders said.

Finally, he discussed the minimum wage, which he believes should be raised to $15 – he called the current level a “starvation wage” – and the need for robust infrastructure spending.

“Those are very specific ideas that I have. I think the secretary has not been quite so clear on those issues,” Sanders said.

Clinton spoke at a rally of workers fighting for the $15 minimum wage earlier this year, cheering their efforts and saying she wanted to “be their champion,” but she did not explicitly endorse a $15 minimum wage.

After the repeated attacks on Clinton and her positions, Sanders softened a bit, saying that he has known Clinton for 25 years, from her time as first lady to her time as his colleague in the Senate. “I like her,” he said. “I respect her and I hope we can run a campaign where we can express the differences of opinion that we have and do it in a way that is straightforward.”

Though Sanders hammered Clinton in his press conference, senators said there were no awkward interactions between the two at the caucus lunch. Sen. Chris Murphy said Clinton mentioned Sanders during her opening comments, saying he had been raising important issues on the campaign. Sen. Tim Kaine added that Clinton praised Sanders for furthering Democratic causes as he campaigns.

And although it may have been uncomfortable for Sanders to watch colleagues heap praise on his primary opponent, Sanders will get his turn. Minority Leader Harry Reid said he had invited Sanders to make a presentation to his Democratic colleagues in the coming weeks. Reid added he was “very impressed” with Clinton, but said he chose “not to endorse her right now."