Michael Cohen, President Trump's personal attorney, challenged MSNBC host Joe Scarborough Wednesday to prove his claim that Trump had leaked his own 2005 tax returns.

".@JoeNBC As #potus @realDonaldTrump personal attorney, I know who has his taxes," Cohen tweeted Wednesday.

"You better have proof to back up your claim and big mouth!"

.@JoeNBC As #potus @realDonaldTrump personal attorney, I know who has his taxes. You better have proof to back up your claim and big mouth! — Michael Cohen (@MichaelCohen212) March 15, 2017

I don't need proof for an opinion 1st graders would get. But you do need proof that Obama tapped Trump's phones. Where is it, Mr. Lawyer? https://t.co/EZfiaEq2yp — Joe Scarborough (@JoeNBC) March 15, 2017

MSNBC's Rachel Maddow on Tuesday night released two pages from Trump's 2005 tax returns on air. Reporter David Cay Johnston, who received the tax returns from an anonymous sending in his mail box, speculated in Maddow's broadcast that Trump could have leaked his own taxes.

Scarborough continued that thread on "Morning Joe" Wednesday morning, claiming that the president had his tax return leaked to the press as a distraction.

"This one tax return is not bad for him because he cherry picked one return from over a decade ago and had it leaked to the press," Scarborough tweeted.

"The Trump camp released one positive tax return to distract from Russia hearings and the Trumpcare meltdown. That's painfully obvious."

The White House on Tuesday released details from the same two pages of Trump's 2005 tax return after Maddow teased the show on Twitter. The returns show that Trump paid about $38 million in taxes on $150 million in income in 2005 and paid an effective tax rate of 24.5 percent.

As a New York real estate mogul and tabloid celebrity, Trump regularly leaked or provided background information to reporters, sometimes even posing as his own fictional spokesman.