Transcript for Russia: Trump canceled meeting because of US 'political situation'

will be a washout here, and heavy snow in the plains. David? Thank you. And president trump in Argentina, after learning his personal lawyer has flipped. The president joining world leaders, including Saudi Arabia's crown prince and Vladimir Putin. That meeting with Putin abruptly cancelled with president trump. Jonathan Karl is in Argentina tonight. Reporter: In Argentina today, an epic greeting. The Russian president and Saudi crown prince, two men portrayed as supervillain dictators, were all smiles. Donald Trump at that moment in the background. He had abruptly cancelled a one-on-one meeting with Vladimir Putin, citing Russia's aggression toward Ukraine. Hopefully they will be able to settle it out soon, because we look forward to meeting with president Putin. Reporter: The Russians aren't buying it. A spokeswoman saying trump cancelled the meeting because of "The domestic political situation in the United States." She was clearly talking about this. Mr. Cohen, how are you feeling? Reporter: The news that Michael Cohen, the president's former lawyer and fixer, had struck a deal with special counsel Robert Mueller. Cohen admitted the trump organization was in talks to build a Moscow trump tower while trump was running for president, something that seems directly at odds with what trump has long said publicly. I have nothing to do with Russia. I have no relationship to Russia whatsoever. I have nothing to do with Russia. I never did. Reporter: ABC news has learned Cohen and a business associate were even talking about giving Putin the $50 million penthouse in trump tower Moscow. Cohen had planned to travel to Moscow during the campaign, but according to the special counsel's court filing, he cancelled that trip on or about June 14th, 2016. That's the same day "The Washington post" broke the story that Russia had hacked the DNC. The president today dismissed the Cohen revelations, saying he continued to run his business while he ran for president and that's, quote, "Very legal and very cool." And that he had "Lightly looked at doing a building somewhere in Russia. Put up zero money, zero guarantees, and didn't do the project." Jon with us live again tonight. And Jon, even though the president cancelled the meeting with Putin, he's calling their relationship very good. Reporter: He said that in an interview tonight. But earlier today, Sarah Sanders said the Mueller investigation, which she called the Russian witch hunt hoax, probably does undermine America's relationship with Russia. David? Jon, thank you. Now to the developing headline.

This transcript has been automatically generated and may not be 100% accurate.