The FBI raided the office of Michael Cohen, a personal lawyer and confidant of President Donald Trump, The New York Times reported Monday.

Stephen Ryan, a lawyer for Cohen, said the US Attorney's office for the Southern District of New York had executed 'a series of search warrants and seized the privileged communications' between Cohen and his clients, according to the Times.

CNN has reached out to Cohen and his attorneys for comment.

Ryan told the Times the search was 'completely inappropriate and unnecessary,' and that federal prosecutors had told him it stemmed partially from a referral by the office of special counsel Robert Mueller.

A person briefed on the search told the Times that one of the topics being investigated was the payment Cohen facilitated to Stephanie Clifford, known as the porn actress Stormy Daniels. The FBI also seized emails, tax documents and business records, including communications between Trump and Cohen, according to the Times.

Cohen is a longtime ally of the President, and admitted earlier this year to setting up a limited liability company in 2016 to pay Daniels. She has alleged she had an affair with Trump a decade earlier, and that the payment was hush money. The White House has denied Daniels' allegations of an affair with Trump.

Asked about the Daniels controversy last week, Trump said he did not know about the payment and declined to comment further, instead referring questions to Cohen.

'You'll have to ask Michael Cohen,' Trump said. 'Michael is my attorney. You'll have to ask Michael.'