President Trump asked Reince Priebus about the former White House chief of staff's testimony in Special Counsel Robert Mueller's investigation, sources confirmed to Fox News on Wednesday -- but they said the talk included “nothing” of substance.

A source with knowledge of the investigation said the conversation was limited to questions like “how did it go?” and “were you treated fairly?”

A second source said the president simply asked Priebus how he was treated and whether investigators were “nice” to him. The source summed up the conversation as “nothing,” saying Trump felt bad that Priebus was forced to sit for hours with Mueller and his staff.

Both sources said the conversation did not go into the substance of Priebus’s testimony.

The president also spoke to White House Counsel Donald McGahn. Sources said Trump asked McGahn to talk to Deputy Attorney General Rod Rosenstein about what they could do regarding Mueller, but that Trump never “ordered” McGahn to fire Mueller.

The New York Times reported Wednesday night that Mueller had learned of two conversations in which Trump asked key witnesses -- one of them Priebus -- about their discussions with investigators. The paper added that at one point, Trump said McGahn should deny its January article that the president once asked McGahn to fire Mueller. McGahn never issued such a denial.

It's unclear when Trump's conversation with Priebus took place, although the Times reported it happened "in recent months."

In addition to investigating Russia’s involvement in the 2016 presidential election, Mueller's team has been looking into whether Trump attempted to obstruct the investigation after he fired FBI Director James Comey last May.

Fox News’ John Roberts contributed to this report.