Michael Cohen, President Donald Trump's former personal attorney, says Trump knew in advance that senior campaign officials planned to meet with a Kremlin-linked lawyer offering dirt on Hillary Clinton at the height of the election, CNN reported.

The report says Cohen claims he and several others were present when Donald Trump Jr., who attended the meeting, informed Trump of the Russians' offer, and that Trump greenlit the meeting.

Cohen reportedly does not have evidence, like tape recordings, proving his claims but is willing to testify about it to the special counsel Robert Mueller under oath.

Cohen is the third Trump associate to hint that Trump may know more than he's letting on about the meeting.

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Michael Cohen, President Donald Trump's former longtime lawyer, says Trump knew in advance about a Russian lawyer's offer to the Trump campaign of dirt on then Democratic nominee Hillary Clinton during the 2016 election, multiple media reports said.

CNN, citing sources with knowledge of the matter, reported that Cohen claims he was one of several people who were present when Donald Trump Jr. informed Trump of the offer. Cohen reportedly says that Trump greenlit the meeting after hearing about it from his son.

Trump Jr. was later one of three top Trump campaign officials, including Paul Manafort and Jared Kushner, who met with the Russian lawyer and several other Kremlin-linked individuals at Trump Tower in June 2016.

CNN and NBC News reported that Cohen does not have physical evidence — like a tape recording — to back up his claim but is willing to testify about it under oath to the special counsel Robert Mueller.

The offer of kompromat from the Russian lawyer, Natalia Veselnitskaya, was pitched in an email to Trump Jr. as being "part of Russia and its government's support for Mr. Trump."

The meeting and any subsequent possible attempts to conceal its purpose now make up a key portion of Mueller's investigation into Russian interference in the election and whether members of the Trump campaign colluded with Moscow to tilt the race in Trump's favor.

Trump and his lawyers maintain that he did not know anything about the meeting in advance. But a central thread in Mueller's investigation is Trump's role in crafting an initially misleading statement Trump Jr. released about the meeting's purpose after news of it was first reported last summer.

The July 2017 statement reads:

"It was a short introductory meeting. I asked Jared and Paul to stop by. We primarily discussed a program about the adoption of Russian children that was active and popular with American families years ago and was since ended by the Russian government, but it was not a campaign issue at the time and there was no follow up. I was asked to attend the meeting by an acquaintance, but was not told the name of the person I would be meeting with beforehand."

Trump Jr. later had to release several subsequent statements as more details about the meeting and its purpose trickled out.

Cohen reportedly did not say anything about whether Trump knew of the meeting when he testified before two congressional committees in 2017, and some legal experts suggested his latest reported claim raises questions about whether he could be charged with lying to Congress.

On Thursday night, the president's current lawyer, Rudy Giuliani, slapped away Cohen's alleged claims, calling him "an incredible liar" who has "a tremendous motive to lie now."

Cohen and Trump have had a falling out over the last few months, particularly after FBI agents raided Cohen's property in April, seizing a multitude of documents and recordings pertaining to his own business dealings and his work for Trump.

The raid was part of a Manhattan US attorney's office investigation into whether Cohen committed bank fraud, wire fraud, and campaign finance violations while working for the president. At the center of the investigation are two payments made during the election to women who claim to have had affairs with Trump.

Cohen reportedly grew frustrated when Trump failed to publicly defend him and the White House distanced itself from him in the aftermath of the raid. In recent weeks, he has been increasingly critical of Trump and spoken out against several of his actions, including his "zero tolerance" immigration policy and his continued broadsides against the FBI and Justice Department.

The rift between the two men comes as Cohen reportedly weighs whether to cooperate with federal investigators. If he does strike a plea deal, it would be part of what's known as a global resolution, meaning that Cohen would have to share all the information he knows that could pertain to any investigation, like the Russia probe.

Cohen is the 3rd Trump associate to hint Trump may know more about the Russia meeting

Michael Cohen. Jeenah Moon/Reuters

Cohen is the third Trump associate to suggest the president knows more about the Trump Tower meeting than he's letting on.

In May, Giuliani refused to issue a blanket denial when asked about Trump's possible knowledge of the Trump Tower meeting.

Giuliani previously told Business Insider he "would be surprised" if Trump knew about the meeting at the time that it happened.

But the former New York City mayor also left open the possibility that Trump may have known but later forgot about the meeting.

"Honestly, I would be surprised if he could remember," Giuliani said. "I couldn't remember. I would say that. I couldn't remember if that happened back then."

In March, Sam Nunberg, a former Trump campaign aide, told MSNBC during a media blitz that Trump "may have done something during the election," adding that he didn't know for sure.

He later told CNN that Robert Mueller, the special counsel investigating Russia's election interference, "thinks Trump is the Manchurian candidate ," a phrase referring to a politician who has been brainwashed to work on behalf of a foreign government.

When CNN's Jake Tapper asked Nunberg whether he believed Trump's statement that he did not know about the meeting in advance, Nunberg said he didn't.

"Jake, I've watched your news reports. You know it's not true," Nunberg said. "He talked about it a week before. And I don't know why he did this. All he had to say was: 'Yeah, we met with the Russians. The Russians offered us something, and we thought they had something, and that was it.' I don't know why he went around trying to hide it."

Nunberg testified to a grand jury in the Russia investigation in March.