FBI raids offices of Trump's personal lawyer

Michael Cohen, President Trump's personal lawyer. (Mark Wilson/Getty Images/AFP)

US President Donald Trump angrily denounced the FBI raid, describing it as a "disgrace" and "whole new level of unfairness."

Railing against what he described as a "witch hunt" and "an attack on our country," Trump pilloried his own attorney general and noting that "many people" were advising him to fire Special Counsel Robert Mueller.

"They found no collusion whatsoever with Russia," a visibly livid Trump said, hours after officials seized documents and other evidence from his attorney.

Cohen's own attorney Stephen Ryan said agents were working in part on the request of Mueller, who is investigating links between Russia and the Trump campaign.

But US media said documents seized in the raid related to the surreptitious payment Cohen made to porn actress Stormy Daniels just ahead of the 2016 presidential election that, according to Daniels, aimed to keep her quiet about her earlier relationship with Trump.

Cohen has been Trump's personal lawyer and confidant for years, advising him on real estate and personal matters, as well as supporting him since he became president.

Cohen also made the US$130,000 payoff to the porn actress Stormy Daniels, ahead of the 2016 election, which she claims was meant to keep her quiet about an alleged affair with Trump.

Ryan lashed out at prosecutors over the raid, which came as Mueller seeks to interview Trump for his sprawling investigation.

Mueller is examining possible collusion between Trump's campaign and Moscow, allegations of corrupt behaviour by Trump campaign lieutenants, and of White House efforts to obstruct the investigation.

"The decision by the US attorney's office in New York to conduct their investigation using search warrants is completely inappropriate and unnecessary," Ryan said.

"It resulted in the unnecessary seizure of protected attorney-client communications between a lawyer and his clients."

The White House did not immediately respond to a request for comment. The New York District Attorney's office and Mueller's Office of the Special Counsel also declined comment.

ALLEGED AFFAIR WITH TRUMP

Cohen, who has worked with Trump for at least a decade, is known as the real estate magnate's "fixer" and "pit bull."

He told ABC News in 2011 that if Trump has a problem with someone, "I do everything in my power to resolve it to Mr Trump's benefit."

"If you do something wrong, I'm going to come at you, grab you by the neck, and I'm not going to let you go until I'm finished," he said.

He does not represent Trump in dealing with Mueller. But his fight with Daniels, whose real name is Stephanie Clifford, has become a political and legal minefield for him and the president.

Last month Daniels told 21 million TV watchers that she had unprotected sex with Trump after meeting with him at a celebrity golf tournament in Lake Tahoe, California in July 2006. That was shortly after Trump's wife Melania gave birth to their son.

After months of pressure, in February Cohen admitted making the US$130,000 payment via a shell company to Daniels as part of a non-disclosure agreement.

He insisted that neither the Trump Organisation, the president's real estate group, nor the Trump campaign was a party to the transaction with Clifford.

"Neither reimbursed me for the payment, either directly or indirectly," Cohen said in a statement.

Trump has not admitted an affair with Daniels. Last week, he broke his silence on the issue and denied knowing anything about the US$130,000 payment to her.

Daniels, though, is seeking to break the non-disclosure agreement, to allow her to freely talk about her relationship with Trump.

Supported by high-powered lawyer Michael Avenatti, she filed a lawsuit in California in March to declare the pact invalid.

Cohen counter-sued saying Daniels is liable for at least US$20 million for violating the hush agreement by publicly discussing the affair on multiple occasions.