CHARLESTON, South Carolina – The Hillary Clinton campaign Saturday night publicly rebuked one of its top outside allies after reports that he planned to make an issue of rival Bernie Sanders’ health – reports he now denies. Meanwhile, the Sanders campaign said they would release a letter testifying to his health in coming weeks.

“Chill out,” Clinton campaign chairman John Podesta tweeted at David Brock, who runs several pro-Clinton groups. “We’re fighting on who would make a better President, not on who has a better Physical Fitness Test.” Politico first reported earlier Saturday that Brock was planning to go on TV to call for the 74-year-old Sanders to release his medical records.

It was a rare public reprimand from a campaign to one of its top supporters – and just 24 hours before the first Democratic presidential debate of the year here. Brock has raised millions of dollars supporting Clinton and runs several groups supporting her bid, including the super PAC Correct the Record, which can coordinate directly with the Clinton campaign.

In a statement to MSNBC Saturday night, Brock called the report “false” and said his group was never planning to go after Sanders’ health.

“Correct The Record is not planning to attack Senator Sanders on the issue of his medical records, nor am I. I’ve said nothing about the issue. This has nothing to do with the Clinton campaign,” Brock said. “Again we are not planning an attack on this and have not even discussed it internally.”

The Sanders campaign immediately moved to fundraise of what they called a “vile super PAC attack.” A Sanders aide told MSNBC the campaign had raised $3.1 million since Tuesday, when Clinton’s campaign stepped up their attacks his single-payer health care plan.

Even as they condemned the reported attack, Sanders aides said that they would release a doctor’s note detailing Sanders’ health ahead of the Iowa Caucuses on February 1.

In his statement, Brock said it was unfortunate that Sanders was fundraising of the report. “Theirs was supposed to be a different kind of campaign, but unfortunately it’s just politics as usual and it’s disappointing to see,” he said.

Podesta’s tweet reflected a distaste inside the Clinton campaign for the proposed attack on Sanders. One Clinton aide mouthed, “what the f**k” when asked about it Saturday night. The attack could open Clinton to her own questions, as Republicans have accused Clinton of having secret health problems.