President Trump is questioning the independence of special counsel Robert Mueller's investigation of election interference by the Russians because it includes people who backed his Democratic opponent in the 2016 campaign.

"I can say that the people that have been hired are all Hillary Clinton supporters," Trump said in a clip of an interview on "Fox and Friends" that will be shown Friday morning.

Trump on Mueller: 'Hes very good friends with Comey, which is very bothersome...people that have been hired are all H. Clinton supporters.' pic.twitter.com/dudG0KcaUx— Kyle Griffin (@kylegriffin1) June 23, 2017

News outlets have reported at least three lawyers Mueller has hired to help conduct his investigation have donated almost exclusively to Democrats, including Clinton.

As part of his investigation, Mueller will probe for possible collusion between the Trump campaign and Russia. The Washington Post reported Mueller will also investigate whether Trump obstructed justice by allegedly telling former FBI Director James Comey that he hoped the bureau would end its probe of Michael Flynn, Trump's first national security adviser. Another report Sunday said Mueller hasn't decided yet whether to investigate Trump.

In the Fox and Friends interview, Trump claimed "there has been no obstruction." He said "it's bothersome" that Mueller and Comey are friends and former colleagues.

"He's very, very good friends with Comey, which is very bothersome," Trump said. "But he's also -- we're going to have to see. I mean we're going to have to see in terms -- look, there has been no obstruction. There has been no collusion. There has been leaking by Comey. But there's been no collusion, no obstruction, and virtually everybody agrees to that. So we'll have to see."

As Trump has stepped up his attacks on Mueller, and is reportedly even considering letting him go, Democrats and Republicans in Congress have defended the former FBI director whose leadership at the helm of the bureau lasted longer than anyone since J. Edgar Hoover.