Michael Avenatti, the lawyer for porn star Stormy Daniels, escalated his battle with President Donald Trump's longtime attorney Michael Cohen over tapes seized by the FBI during April raids on Cohen's home, office, and hotel room.

On Thursday, Avenatti sent a letter to Cohen asking them to turn over to him all tapes of conversations between Cohen and Keith Davidson, Daniels's initial attorney for the hush-money deal meant to stifle her allegations of an affair with Trump.

The letter followed Avenatti's Wednesday court appearance , where he expanded on his allegation that Cohen's side had selectively leaked the audio recordings to the media.

Cohen is under criminal investigation in the Southern District of New York. He has not been charged with a crime.

Michael Avenatti, the attorney for porn star Stormy Daniels, escalated his battle with President Donald Trump's longtime attorney Michael Cohen over tapes seized by the FBI during April raids on Cohen's home, office, and hotel room.

On Thursday, Avenatti sent a letter to Cohen and Stephen Ryan, his lead attorney, asking them to turn over to him all tapes of conversations between Cohen and Keith Davidson, Daniels's initial attorney for the nondisclosure deal meant to stifle her allegations of an affair with Trump, in which Daniels's matter was discussed.

The letter followed Avenatti's Wednesday court appearance, in which he expanded on his allegation that Cohen's side had selectively leaked the audio recordings to the media, withholding other tapes such as ones Avenatti claims exist of conversations between Cohen and Trump. Avenatti then went on a media blitz following his court appearance in which he continued to hammer away at the subject, demanding that Cohen's side release publicly all the recordings they have.

Cohen, who facilitated Daniels's hush money agreement, is the focus of a criminal investigation in the Southern District of New York centered around whether he violated campaign-finance laws or committed bank fraud. He has not been charged with a crime.

Avenatti's client, Daniels, whose real name is Stephanie Clifford, is suing Cohen and Trump in California, seeking to get out of the deal that paid her $130,000 for her silence about the alleged 2006 affair with Trump. Cohen facilitated that agreement just prior to the 2016 presidential election, and Trump recently admitted to reimbursing Cohen for that expenditure via his recently filed financial disclosure.

Michael Cohen. Shannon Stapleton/Reuters Last week, Avenatti first made this allegation about the recordings. It was not clear to what exactly Avenatti was referring. The attorney did not point to any specific media reports, and none appeared to be based off such leaks in the days that followed.

But during the latest hearing in Cohen's criminal case, Avenatti told US District Judge Kimba Wood that he was recently contacted by a reporter who said he had a recording that he believed was made by Cohen.

"From what I understood there were audio recordings" between Cohen and Davidson, "regarding attorney-client privilege," Avenatti said.

Ryan did not deny that such tapes existed when he responded in court, but said he was "unaware" of any that were released to the media. Ryan said such recordings were guarded by his law firm "under lock and key."

"If we had released the audiotape to a reporter, it would have been the biggest story in America," Ryan said.

Avenatti argued that the existence of such tapes, which he said contain privileged communications involving his client, is reason for Daniels to intervene in the case.

"Just like the Nixon tapes years ago we now have what I will refer to as the Trump Tapes," Avenatti told reporters outside the lower Manhattan courthouse as he called for other recordings to be released publicly.

In his letter to Cohen and Ryan, Avenatti called Ryan's comments about the recordings "astonishing."

"This is a very serious matter causing immense prejudice to my client," he said, demanding the tapes as well as all privileged material related to Daniels that is in their possession.