President Trump warned the special counsel investigating Russia not to look into his business or personal finances during an interview on Wednesday.

Trump was asked by the New York Times whether Robert Mueller would be crossing a red line if he expanded the probe into the Trump family empire.

“I would say yes,” Trump said about the red line. “I think that’s a violation. Look, this is about Russia.”

The Times also reported that Trump criticized Mueller for running an office rife with conflicts of interest.

Trump did not say what he would do if Mueller subpoenaed financial records. However, the president reportedly considered firing the special counsel in the past.

The president has repeatedly refused to release his tax returns or the financial information for his sprawling real estate empire.

Mueller is looking into collusion between Russia and Trump campaign aides during the 2016 presidential election.