Bernie Sanders downplayed his relationship with Barack Obama Wednesday, after Joe Biden’s campaign denounced the Vermont senator’s new ad featuring clips of him with the former president.

“We have worked with President Obama. I’m not going to say he and I are best friends, we talk every now and then,” Sen. Sanders (I-Vt.) told reporters when asked what he hoped to achieve with the ad.

“I wanted to make it clear, because there’s a lot of statements about my relationship with Obama, to say that I worked with him and respect him and look forward to working with him,” Sanders added.

The statements Sanders was referring to stem from a report in The Atlantic published in February, which said he considered a 2012 Democratic primary challenge to Obama.

Disillusioned with Obama’s centrist policies, Sanders reportedly brought up the idea of challenging him to fellow Vermont Sen. Patrick Leahy in 2011. Leahy immediately warned Obama’s campaign, according to the magazine.

The 2020 hopeful went on to make multiple media appearances that year in which he shared his disappointment with Obama’s job performance.

Biden’s campaign released an ad featuring the accusations in the article ahead of the South Carolina primary.

In Sanders’ newly released spot, Obama can be heard praising the senator, describing him as “somebody who has the virtue of saying exactly what he believes.”

“People are ready for a call to action. They want honest leadership who cares about them. They want somebody who’s gonna fight for them. And they will find it in Bernie,” Obama said in a clip used in the ad.

Biden spokesman Andrew Bates decried the ad by comparing it to one by recent 2020 dropout Michael Bloomberg.

“As recent history has proven, no quantity of ads can rewrite history — and there’s no substitute for genuinely having the back of the best president of our lifetimes,” he said.

When speaking to reporters Wednesday, Sanders offered Obama genuine praise for his restraint in getting involved in the 2020 primary.

“I have not the slightest doubt, that there is enormous pressure on President Obama to jump into this race and support Joe Biden, and some of you may have read the other day that he said no,” the presidential hopeful said, adding, “He thinks the best role that he can play, and I agree with him, is to support the winner, so he doesn’t create more division. And I think he’s right, but that’s not easy for him to do, and I very much appreciate his willingness to do that.”