"Mark Corallo was instructed not to speak to the press, indeed not to even answer his phone," Wolff writes. "Later that week, Corallo, seeing no good outcome -- and privately confiding that he believed the meeting on Air Force One represented a likely obstruction of justice -- quit."

The statement the president reportedly dictated concerned the purpose of a June 2016 meeting between Trump's eldest son, Donald Trump Jr., senior advisor Jared Kushner, then-campaign chairman Paul Manafort and a Russian lawyer. 

That initial explanation suggested the primary purpose of the meeting was to discuss Russian adoptions. That was later shown to be misleading, and Trump Jr. has said that the purpose of the meeting was to discuss potential dirt on political rival Hillary Clinton. 

Advisors to the president told The Washington Post in July that the initial statement could raise questions about whether the president is attempting to hide something.