Transcript for Trump: 'A lot of people are saying they had spies in my campaign'

President trump taking aim at the justice department, the FBI tonight, saying that if the FBI infiltrated his campaign for political purposes, it would be, a, quote, disgrace. But has the president provided any proof that actually happened? Here's ABC's senior white house correspondent Cecilia Vega tonight. Reporter: President trump today dialing up the outrage at the unsubstantiated claim that the FBI may have used spies to infiltrate his campaign. A lot of people are saying they had spies in my campaign. If they had spies in my campaign, that would be a disgrace to this country. That would be very illegal, aside from everything else. Reporter: There is no evidence that actually happened. The president's growing anger stems from a "New York Times" report that claims as part of the 2016 investigation into Russian meddling, the FBI used an informant to question two trump campaign associates about their contacts with Russians. Some man got paid based on what I read in the newspapers and on what you reported, some person got paid a lot of money. Reporter: Law enforcement experts say, in reality, the use of such informants is routine. And that news report made no mention of spies infiltrating the trump team. But that did not stop the president from tweeting an extraordinary edict. "I hereby demand" a new investigation into "Whether the fbi/doj infiltrated or surveilled his campaign." Reporter: Deputy attorney general rod Rosenstein and FBI director Christopher WRAY summoned to the white house yesterday. Rosenstein ordering the justice department's inspector general to investigate the president's concerns as part of an ongoing probe. In the president's crosshairs, Rosenstein, who just weeks ago vowed to stand his ground. The department of justice is not going to be extorted. We're going to do what's required by the rule of law. Reporter: But today, president trump refused to give Rosenstein a vote of support. Do you have confidence in rod Rosenstein? What is your next question, please? Cecilia Vega with us from inside the briefing room tonight. Cecilia, the American people were told before the election that the FBI was investigating Russian meddling, legal observers say FBI informants would be standard in that case. As you report tonight, the president is now saying something very different here, saying there were spies inside his campaign, potentially. Is the white house providing any proof tonight? Reporter: Well, David, none yet. And this is not the first time the president has raised this question about spies being in his campaign. It's also not the first time he's peddled an unsubstantiated claim. He said everything from president Obama was not born in this country to president Obama had trump tower wiretapped. David? Cecilia, there is a breaking headline late today regarding Michael Cohen, president trump's former personal lawyer who was raided by the FBI and is under investigation. "The New York Times" reporting tonight that a long-time partner of Cohen's in the taxi business has now taken a plea deal. He agreed to plead guilty to one count of tax evasion and promised to cooperate with state and federal investigators. He is a Russian immigrant, known as the taxi king. Let's get to Cecilia tonight. What could this mean for Michael Cohen? Reporter: Well, it could potentially mean more trouble, David, remains to be seen. Friedman will seven no jail time for cooperating. Investigators could use this to pressure Michael Cohen. Some privately said that if an investigation could lead to his businesses, it could push him to cooperate. Cecilia, thank you. We have new details tonight about the school bus driver involved in that fatal crash we

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