White House officials have a "great deal of concern" about news reports that suggest members of special counsel Robert Mueller's team may have harbored political biases against President Trump, press secretary Sarah Sanders said Tuesday.

"I think we've seen some reports that certainly cause a great deal of concern and we hope those are looked at and investigated," Sanders told reporters at the White House.

Her comment came days after the New York Times and other outlets reported Mueller had reassigned Peter Strzok, a top FBI investigator, over the summer in response to the discovery that Strzok had sent anti-Trump text messages to a colleague.

The news that a politically biased investigator had spent months working on the probe of Russian interference in the 2016 election — as well as on the investigation of Hillary Clinton's emails — as fueled more criticism of the Mueller probe. Trump's allies have long argued that Mueller's decision to hire some lawyers who had donated to Democrats undermined the credibility of the investigation.

Although news reports suggested Tuesday that Mueller's team had issued a subpoena to a bank potentially related to Trump's personal finances, Sanders noted the president's lawyer had called the reports "completely false."

"We've confirmed this with the bank and other sources," Sanders said.

The White House press secretary called the speculation that immediately followed those reports an example of "the media going too far, too fast."