President Donald Trump directed retired Lt. Gen. Michael Flynn to reach out to the Russians during the 2016 presidential campaign, according to a new report.

ABC News' Brian Ross said Friday morning Flynn has promised special counsel Robert Mueller, who is spearheading the Department of Justice's Russia probe, "full cooperation." That includes, according to Ross, testifying against Trump, members of the Trump family, and White House officials.

Part of the testimony, Ross said, will be that Trump ordered Flynn to contact the Russians.

It's unclear exactly why Trump allegedly asked Flynn to reach out to America's Cold War foe, but Trump himself has denied ever doing such a thing.

Court papers were not specific about who ordered Flynn to make contact:

"On or about December 22, 2016, a very senior member of the Presidential Transition Team directed Flynn to contact foreign officials from foreign governments, including Russia."

Flynn pleaded guilty to lying to the FBI in a Washington, D.C. federal court Friday morning. He is reportedly cooperating with Mueller's team as the DOJ tries to ascertain whether the Trump campaign colluded with Russia.

Ross also reported that Flynn decided to cooperate with Mueller within the last 24 hours and that he feels he's doing his patriotic duty by testifying against Trump. He also is facing massive legal bills that will likely lead to having to sell his house.

Flynn served as Trump's national security adviser in the West Wing for 24 days before he resigned Feb. 13 after it became clear that he failed to disclose contacts with Russians.

Mueller's team already has indicted former Trump campaign chairman Paul Manafort, Manafort's business associate Rick Gates, and former Trump campaign adviser George Papadopoulos in the ever-widening Russia investigation that has dogged Trump's presidency from the start.

Reports over the last several months claimed Flynn had a potential conflict of interest while working for Trump, which he may have used to sway U.S. policy.