Special counsel Robert Mueller. President Donald Trump's outside legal team is reportedly evaluating potential conflicts of interest among Mueller and his team of attorneys, in an effort to control the independent investigation. Alex Wong/Getty Images President Donald Trump is incensed at reports that Robert Mueller, a former FBI director leading the independent investigation into possible collusion between the Trump campaign and Russia, is investigating Trump's business dealings and finances, including his tax returns.

The Washington Post reported on Thursday that Trump has told aides he is particularly upset at the prospect of the investigators having access to several years of his tax returns.

Every president Since Jimmy Carter has released his tax returns, but Trump has refused, after initially promising to make them public following an IRS audit.

In a Wednesday interview with The New York Times, Trump said digging into his finances would be a "violation" of the investigation's limits.

"If you're looking at Russian collusion, the president’s tax returns would be outside that investigation," an adviser to the president told the Post.

But legal experts say Trump's financial history and business dealings are properly within the scope of the probe.

"This is Ken Starr times 1,000," a lawyer involved in the case told the Post, referring to the independent counsel who led the investigation into Bill Clinton that led to his impeachment trial in 1998. "Of course, it’s going to go into his finances."

The president has also denied having any business ties with Russia.

"They said I made money from Russia. I don't," Trump told the Times on Wednesday. "It's not my thing. I don't, I don't do that. Over the years, I've looked at maybe doing a deal in Russia, but I never did one. Other than I held the Miss Universe pageant there eight, nine years."

Mueller's team is already investigating the finances of White House senior adviser Jared Kushner, while federal prosecutors also looking into the financial dealings of Trump associates, including former campaign chairman Paul Manafort and former national security adviser Michael Flynn.

Trump's team of personal lawyers is engaged in an effort to control the scope of Mueller's Russia investigation, according to the Post report.

The attorneys are evaluating potential conflicts of interest among Mueller and his team and are reportedly advising the president on his power to pardon his aides, family members, and even himself in connection with the investigation into possible collusion between the Trump campaign and Russia.

Trump has publicly accused Mueller and lawyers involved in the Russia probe of having conflicts of interest due to their personal and professional ties to Democrats. At least seven of the 15 attorneys Mueller has hired have made donations to Democratic politicians.

During his Wednesday interview with the Times, Trump escalated his criticism of his Justice Department, claiming that he would not have hired Attorney General Jeff Sessions had he known Sessions would recuse himself from the Russia investigation. He also suggested a left-leaning bias from Deputy Attorney General Rod Rosenstein.

The spokesman for Trump's legal team, Mark Corallo, resigned on Thursday after reportedly objecting to public criticism of Mueller, the Post wrote.