Transcript for Mueller inquired about Comey and Flynn firings: Sources
We move on to president trump. He's gearing up for his final day of diplomacy in New York. North Korea is responding to the president's combative united nations speech where trump threatened to destroy north Korea. Their foreign minister dismissed the president's speech as the sound of a dog barking and Iran slammed it and trump made a decision whether to pull out of the nuclear deal but will not say what it is yet and in Washington, the Russian investigation is intensifying. Special counsel Robert Mueller has asked the white house for documents about the firings of James Comey and Michael Flynn and the oval office meeting between the president and top Russian diplomats. Let's get more on that from our chief white house correspondent Jon Karl. Mueller really tightening the noose focusing directly on the white house. The clearest indication his investigation is going inside the white house and looking at the actions of president trump himself. You remember the president has said over and over again I'm not under investigation. Now it sure looks like he is. The firing of Mueller, I mean the firing of Comey, the firing of Flynn, also the blatantly false statement that press secretary Sean spicer put out the day that Comey was fired explaining why he was fired. All of that is what he's looking to. The president clearly under investigation right now. Meantime, we know his former campaign chairman Paul manafort has really been in the crosshairs of Robert Mueller and now we also know that thousands potentially of e-mails have been turned over to Mueller. Yeah, blockbuster story in "The Washington post" on in that shows among many other things that manafort was offering to set up a briefing on the campaign with one of Russia's richest oligarchs, interesting response from Bloomberg from Ty Cobb, the president's lawyer, it is truly shocking if manafort was trying to profit on his ties to trump and that he would never have tolerated -- no evidence the briefing actually happened. No evidence that briefing happened but with manafort you've seen efforts by the president to distance himself from the former campaign manager going several months back but they appear to be in contact later in the year into the presidency. The key thing, the big question, George is whether or not Mueller is trying to flip manafort. Trying to get him to give evidence against the president. We will see. Jon Karl, thanks very much.
This transcript has been automatically generated and may not be 100% accurate.