WASHINGTON -- The FBI on Monday raided the office of Michael Cohen, US President Donald Trump's personal lawyer, seizing documents related to topics including his payment to an adult film actress, according to US media.

The New York Times reported that federal prosecutors in Manhattan obtained a search warrant after receiving a referral from special counsel Robert Mueller, but the raid does not appear to be directly related to Mueller's investigation.

The seized documents also reportedly include emails, tax documents, business records and communications between Cohen and Trump.

Cohen's lawyer, Stephen Ryan, told The Times that the search was "completely inappropriate and unnecessary."

Among the documents federal agents seized were those related to Cohen's 130,000-US-dollar hush money payment to Stormy Daniels, an adult film actress who has alleged having an affair with Trump in 2006.

The payment was made to Daniels, whose legal name is Stephanie Clifford, for her silence about the alleged affair, just days before the 2016 US presidential election. Cohen has denied it violated campaign finances laws.

Last week, Trump denied knowledge of the payment. It was the first time that the president has publicly addressed the issue. The White House has said that Trump denies there was a relationship.

Daniels was trying to void a non-disclosure agreement that she signed for the payment, while her lawyer filed a renewed motion on Sunday to depose Trump and Cohen over the matter.

Cohen, who has been Trump's personal lawyer for years, has reportedly a role in aspects of the special counsel's investigation into the alleged Russian meddling in the 2016 election and possible collusion between the Trump campaign and Moscow.